The only new code in this PR is this `Callback` implementation. Everything else was here previously.
Evaluate adding createAsync() to the RxJava adapters.
This would use `enqueue` instead of `execute` to defer threading to OkHttp's `Dispatcher` instead of blocking a scheduler (or application) thread. This would allow re-using 90% of the built-in machinery around things like type parsing, `Result`/body handling, etc.
retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallOnSubscribe.java retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapter.java retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapterFactory.java
retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallArbiter.java retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallEnqueueOnSubscribe.java retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallExecuteOnSubscribe.java retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapter.java retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapterFactory.java
retrofit-adapters/rxjava/src/test/java/retrofit2/adapter/rxjava/AsyncTest.java
diff --git a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallArbiter.java b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallArbiter.java
new file mode 100644
index 0000000000..34b0b004a5
--- /dev/null
+++ b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallArbiter.java
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2016 Jake Wharton
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package retrofit2.adapter.rxjava;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import retrofit2.Call;
+import retrofit2.Response;
+import rx.Producer;
+import rx.Subscriber;
+import rx.Subscription;
+import rx.exceptions.CompositeException;
+import rx.exceptions.Exceptions;
+import rx.plugins.RxJavaPlugins;
+
+final class CallArbiter<T> extends AtomicInteger implements Subscription, Producer {
+  private static final int STATE_WAITING = 0;
+  private static final int STATE_REQUESTED = 1;
+  private static final int STATE_HAS_RESPONSE = 2;
+  private static final int STATE_TERMINATED = 3;
+
+  private final Call<T> call;
+  private final Subscriber<? super Response<T>> subscriber;
+
+  private volatile Response<T> response;
+
+  CallArbiter(Call<T> call, Subscriber<? super Response<T>> subscriber) {
+    super(STATE_WAITING);
+
+    this.call = call;
+    this.subscriber = subscriber;
+  }
+
+  @Override public void unsubscribe() {
+    call.cancel();
+  }
+
+  @Override public boolean isUnsubscribed() {
+    return call.isCanceled();
+  }
+
+  @Override public void request(long amount) {
+    if (amount == 0) {
+      return;
+    }
+    while (true) {
+      int state = get();
+      switch (state) {
+        case STATE_WAITING:
+          if (compareAndSet(STATE_WAITING, STATE_REQUESTED)) {
+            return;
+          }
+          break; // State transition failed. Try again.
+
+        case STATE_HAS_RESPONSE:
+          if (compareAndSet(STATE_HAS_RESPONSE, STATE_TERMINATED)) {
+            deliverResponse(response);
+            return;
+          }
+          break; // State transition failed. Try again.
+
+        case STATE_REQUESTED:
+        case STATE_TERMINATED:
+          return; // Nothing to do.
+
+        default:
+          throw new IllegalStateException("Unknown state: " + state);
+      }
+    }
+  }
+
+  void emitResponse(Response<T> response) {
+    while (true) {
+      int state = get();
+      switch (state) {
+        case STATE_WAITING:
+          this.response = response;
+          if (compareAndSet(STATE_WAITING, STATE_HAS_RESPONSE)) {
+            return;
+          }
+          break; // State transition failed. Try again.
+
+        case STATE_REQUESTED:
+          if (compareAndSet(STATE_REQUESTED, STATE_TERMINATED)) {
+            deliverResponse(response);
+            return;
+          }
+          break; // State transition failed. Try again.
+
+        case STATE_HAS_RESPONSE:
+        case STATE_TERMINATED:
+          throw new AssertionError();
+
+        default:
+          throw new IllegalStateException("Unknown state: " + state);
+      }
+    }
+  }
+
+  private void deliverResponse(Response<T> response) {
+    try {
+      if (!isUnsubscribed()) {
+        subscriber.onNext(response);
+      }
+    } catch (Throwable t) {
+      Exceptions.throwIfFatal(t);
+      try {
+        subscriber.onError(t);
+      } catch (Throwable inner) {
+        Exceptions.throwIfFatal(inner);
+        CompositeException composite = new CompositeException(t, inner);
+        RxJavaPlugins.getInstance().getErrorHandler().handleError(composite);
+      }
+      return;
+    }
+    try {
+      subscriber.onCompleted();
+    } catch (Throwable t) {
+      Exceptions.throwIfFatal(t);
+      RxJavaPlugins.getInstance().getErrorHandler().handleError(t);
+    }
+  }
+
+  void emitError(Throwable t) {
+    set(STATE_TERMINATED);
+
+    if (!isUnsubscribed()) {
+      try {
+        subscriber.onError(t);
+      } catch (Throwable inner) {
+        Exceptions.throwIfFatal(inner);
+        CompositeException composite = new CompositeException(t, inner);
+        RxJavaPlugins.getInstance().getErrorHandler().handleError(composite);
+      }
+    }
+  }
+}
diff --git a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallEnqueueOnSubscribe.java b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallEnqueueOnSubscribe.java
new file mode 100644
index 0000000000..7dcf917c39
--- /dev/null
+++ b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallEnqueueOnSubscribe.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2016 Jake Wharton
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package retrofit2.adapter.rxjava;
+
+import retrofit2.Call;
+import retrofit2.Callback;
+import retrofit2.Response;
+import rx.Observable.OnSubscribe;
+import rx.Subscriber;
+import rx.exceptions.Exceptions;
+
+final class CallEnqueueOnSubscribe<T> implements OnSubscribe<Response<T>> {
+  private final Call<T> originalCall;
+
+  CallEnqueueOnSubscribe(Call<T> originalCall) {
+    this.originalCall = originalCall;
+  }
+
+  @Override public void call(Subscriber<? super Response<T>> subscriber) {
+    // Since Call is a one-shot type, clone it for each new subscriber.
+    Call<T> call = originalCall.clone();
+    final CallArbiter<T> arbiter = new CallArbiter<>(call, subscriber);
+    subscriber.add(arbiter);
+    subscriber.setProducer(arbiter);
+
+    call.enqueue(new Callback<T>() {
+      @Override public void onResponse(Call<T> call, Response<T> response) {
+        arbiter.emitResponse(response);
+      }
+
+      @Override public void onFailure(Call<T> call, Throwable t) {
+        Exceptions.throwIfFatal(t);
+        arbiter.emitError(t);
+      }
+    });
+  }
+}
diff --git a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallExecuteOnSubscribe.java b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallExecuteOnSubscribe.java
new file mode 100644
index 0000000000..593770aa77
--- /dev/null
+++ b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallExecuteOnSubscribe.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2016 Jake Wharton
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package retrofit2.adapter.rxjava;
+
+import retrofit2.Call;
+import retrofit2.Response;
+import rx.Observable.OnSubscribe;
+import rx.Subscriber;
+import rx.exceptions.Exceptions;
+
+final class CallExecuteOnSubscribe<T> implements OnSubscribe<Response<T>> {
+  private final Call<T> originalCall;
+
+  CallExecuteOnSubscribe(Call<T> originalCall) {
+    this.originalCall = originalCall;
+  }
+
+  @Override public void call(Subscriber<? super Response<T>> subscriber) {
+    // Since Call is a one-shot type, clone it for each new subscriber.
+    Call<T> call = originalCall.clone();
+    CallArbiter<T> arbiter = new CallArbiter<>(call, subscriber);
+    subscriber.add(arbiter);
+    subscriber.setProducer(arbiter);
+
+    Response<T> response;
+    try {
+      response = call.execute();
+    } catch (Throwable t) {
+      Exceptions.throwIfFatal(t);
+      arbiter.emitError(t);
+      return;
+    }
+    arbiter.emitResponse(response);
+  }
+}
diff --git a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallOnSubscribe.java b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallOnSubscribe.java
deleted file mode 100644
index 7e0f53969c..0000000000
--- a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/CallOnSubscribe.java
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Copyright (C) 2016 Jake Wharton
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package retrofit2.adapter.rxjava;
-
-import java.util.concurrent.atomic.AtomicInteger;
-import retrofit2.Call;
-import retrofit2.Response;
-import rx.Observable.OnSubscribe;
-import rx.Producer;
-import rx.Subscriber;
-import rx.Subscription;
-import rx.exceptions.CompositeException;
-import rx.exceptions.Exceptions;
-import rx.plugins.RxJavaPlugins;
-
-final class CallOnSubscribe<T> implements OnSubscribe<Response<T>> {
-  private final Call<T> originalCall;
-
-  CallOnSubscribe(Call<T> originalCall) {
-    this.originalCall = originalCall;
-  }
-
-  @Override public void call(Subscriber<? super Response<T>> subscriber) {
-    // Since Call is a one-shot type, clone it for each new subscriber.
-    Call<T> call = originalCall.clone();
-    CallArbiter<T> arbiter = new CallArbiter<>(call, subscriber);
-    subscriber.add(arbiter);
-    subscriber.setProducer(arbiter);
-
-    Response<T> response;
-    try {
-      response = call.execute();
-    } catch (Throwable t) {
-      Exceptions.throwIfFatal(t);
-      arbiter.emitError(t);
-      return;
-    }
-    arbiter.emitResponse(response);
-  }
-
-  static final class CallArbiter<T> extends AtomicInteger implements Subscription, Producer {
-    private static final int STATE_WAITING = 0;
-    private static final int STATE_REQUESTED = 1;
-    private static final int STATE_HAS_RESPONSE = 2;
-    private static final int STATE_TERMINATED = 3;
-
-    private final Call<T> call;
-    private final Subscriber<? super Response<T>> subscriber;
-
-    private volatile Response<T> response;
-
-    CallArbiter(Call<T> call, Subscriber<? super Response<T>> subscriber) {
-      super(STATE_WAITING);
-
-      this.call = call;
-      this.subscriber = subscriber;
-    }
-
-    @Override public void unsubscribe() {
-      call.cancel();
-    }
-
-    @Override public boolean isUnsubscribed() {
-      return call.isCanceled();
-    }
-
-    @Override public void request(long amount) {
-      if (amount == 0) {
-        return;
-      }
-      while (true) {
-        int state = get();
-        switch (state) {
-          case STATE_WAITING:
-            if (compareAndSet(STATE_WAITING, STATE_REQUESTED)) {
-              return;
-            }
-            break; // State transition failed. Try again.
-
-          case STATE_HAS_RESPONSE:
-            if (compareAndSet(STATE_HAS_RESPONSE, STATE_TERMINATED)) {
-              deliverResponse(response);
-              return;
-            }
-            break; // State transition failed. Try again.
-
-          case STATE_REQUESTED:
-          case STATE_TERMINATED:
-            return; // Nothing to do.
-
-          default:
-            throw new IllegalStateException("Unknown state: " + state);
-        }
-      }
-    }
-
-    void emitResponse(Response<T> response) {
-      while (true) {
-        int state = get();
-        switch (state) {
-          case STATE_WAITING:
-            this.response = response;
-            if (compareAndSet(STATE_WAITING, STATE_HAS_RESPONSE)) {
-              return;
-            }
-            break; // State transition failed. Try again.
-
-          case STATE_REQUESTED:
-            if (compareAndSet(STATE_REQUESTED, STATE_TERMINATED)) {
-              deliverResponse(response);
-              return;
-            }
-            break; // State transition failed. Try again.
-
-          case STATE_HAS_RESPONSE:
-          case STATE_TERMINATED:
-            throw new AssertionError();
-
-          default:
-            throw new IllegalStateException("Unknown state: " + state);
-        }
-      }
-    }
-
-    private void deliverResponse(Response<T> response) {
-      try {
-        if (!isUnsubscribed()) {
-          subscriber.onNext(response);
-        }
-      } catch (Throwable t) {
-        Exceptions.throwIfFatal(t);
-        try {
-          subscriber.onError(t);
-        } catch (Throwable inner) {
-          Exceptions.throwIfFatal(inner);
-          CompositeException composite = new CompositeException(t, inner);
-          RxJavaPlugins.getInstance().getErrorHandler().handleError(composite);
-        }
-        return;
-      }
-      try {
-        subscriber.onCompleted();
-      } catch (Throwable t) {
-        Exceptions.throwIfFatal(t);
-        RxJavaPlugins.getInstance().getErrorHandler().handleError(t);
-      }
-    }
-
-    void emitError(Throwable t) {
-      set(STATE_TERMINATED);
-
-      if (!isUnsubscribed()) {
-        try {
-          subscriber.onError(t);
-        } catch (Throwable inner) {
-          Exceptions.throwIfFatal(inner);
-          CompositeException composite = new CompositeException(t, inner);
-          RxJavaPlugins.getInstance().getErrorHandler().handleError(composite);
-        }
-      }
-    }
-  }
-}
diff --git a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapter.java b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapter.java
index 8d8f3776a2..f14c47181a 100644
--- a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapter.java
+++ b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapter.java
@@ -26,15 +26,17 @@
 final class RxJavaCallAdapter<R> implements CallAdapter<R, Object> {
   private final Type responseType;
   private final Scheduler scheduler;
+  private final boolean isAsync;
   private final boolean isResult;
   private final boolean isBody;
   private final boolean isSingle;
   private final boolean isCompletable;
 
-  RxJavaCallAdapter(Type responseType, Scheduler scheduler, boolean isResult, boolean isBody,
-      boolean isSingle, boolean isCompletable) {
+  RxJavaCallAdapter(Type responseType, Scheduler scheduler, boolean isAsync, boolean isResult,
+      boolean isBody, boolean isSingle, boolean isCompletable) {
     this.responseType = responseType;
     this.scheduler = scheduler;
+    this.isAsync = isAsync;
     this.isResult = isResult;
     this.isBody = isBody;
     this.isSingle = isSingle;
@@ -46,7 +48,9 @@ final class RxJavaCallAdapter<R> implements CallAdapter<R, Object> {
   }
 
   @Override public Object adapt(Call<R> call) {
-    OnSubscribe<Response<R>> callFunc = new CallOnSubscribe<>(call);
+    OnSubscribe<Response<R>> callFunc = isAsync
+        ? new CallEnqueueOnSubscribe<>(call)
+        : new CallExecuteOnSubscribe<>(call);
 
     OnSubscribe<?> func;
     if (isResult) {
diff --git a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapterFactory.java b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapterFactory.java
index 2834516791..184750d059 100644
--- a/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapterFactory.java
+++ b/retrofit-adapters/rxjava/src/main/java/retrofit2/adapter/rxjava/RxJavaCallAdapterFactory.java
@@ -61,7 +61,15 @@ public final class RxJavaCallAdapterFactory extends CallAdapter.Factory {
    * by default.
    */
   public static RxJavaCallAdapterFactory create() {
-    return new RxJavaCallAdapterFactory(null);
+    return new RxJavaCallAdapterFactory(null, false);
+  }
+
+  /**
+   * Returns an instance which creates asynchronous observables. Applying
+   * {@link Observable#subscribeOn} has no effect on stream types created by this factory.
+   */
+  public static RxJavaCallAdapterFactory createAsync() {
+    return new RxJavaCallAdapterFactory(null, true);
   }
 
   /**
@@ -70,13 +78,15 @@ public static RxJavaCallAdapterFactory create() {
    */
   public static RxJavaCallAdapterFactory createWithScheduler(Scheduler scheduler) {
     if (scheduler == null) throw new NullPointerException("scheduler == null");
-    return new RxJavaCallAdapterFactory(scheduler);
+    return new RxJavaCallAdapterFactory(scheduler, false);
   }
 
   private final Scheduler scheduler;
+  private final boolean isAsync;
 
-  private RxJavaCallAdapterFactory(Scheduler scheduler) {
+  private RxJavaCallAdapterFactory(Scheduler scheduler, boolean isAsync) {
     this.scheduler = scheduler;
+    this.isAsync = isAsync;
   }
 
   @Override
@@ -89,7 +99,7 @@ private RxJavaCallAdapterFactory(Scheduler scheduler) {
     }
 
     if (isCompletable) {
-      return new RxJavaCallAdapter(Void.class, scheduler, false, true, false, true);
+      return new RxJavaCallAdapter(Void.class, scheduler, isAsync, false, true, false, true);
     }
 
     boolean isResult = false;
@@ -121,6 +131,7 @@ private RxJavaCallAdapterFactory(Scheduler scheduler) {
       isBody = true;
     }
 
-    return new RxJavaCallAdapter(responseType, scheduler, isResult, isBody, isSingle, false);
+    return new RxJavaCallAdapter(responseType, scheduler, isAsync, isResult, isBody, isSingle,
+        false);
   }
 }

diff --git a/retrofit-adapters/rxjava/src/test/java/retrofit2/adapter/rxjava/AsyncTest.java b/retrofit-adapters/rxjava/src/test/java/retrofit2/adapter/rxjava/AsyncTest.java
new file mode 100644
index 0000000000..2c27037693
--- /dev/null
+++ b/retrofit-adapters/rxjava/src/test/java/retrofit2/adapter/rxjava/AsyncTest.java
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2017 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package retrofit2.adapter.rxjava;
+
+import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicReference;
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestRule;
+import retrofit2.Retrofit;
+import retrofit2.http.GET;
+import rx.Completable;
+import rx.exceptions.CompositeException;
+import rx.exceptions.Exceptions;
+import rx.observers.AsyncCompletableSubscriber;
+import rx.observers.TestSubscriber;
+import rx.plugins.RxJavaErrorHandler;
+import rx.plugins.RxJavaPlugins;
+
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static okhttp3.mockwebserver.SocketPolicy.DISCONNECT_AFTER_REQUEST;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assert.assertFalse;
+
+public final class AsyncTest {
+  @Rule public final MockWebServer server = new MockWebServer();
+  @Rule public final TestRule pluginsReset = new RxJavaPluginsResetRule();
+
+  interface Service {
+    @GET("/") Completable completable();
+  }
+
+  private Service service;
+  @Before public void setUp() {
+    Retrofit retrofit = new Retrofit.Builder()
+        .baseUrl(server.url("/"))
+        .addCallAdapterFactory(RxJavaCallAdapterFactory.createAsync())
+        .build();
+    service = retrofit.create(Service.class);
+  }
+
+  @Test public void success() throws InterruptedException {
+    TestSubscriber<Void> subscriber = new TestSubscriber<>();
+    service.completable().subscribe(subscriber);
+    assertFalse(subscriber.awaitValueCount(1, 1, SECONDS));
+
+    server.enqueue(new MockResponse());
+    subscriber.awaitTerminalEvent(1, SECONDS);
+    subscriber.assertCompleted();
+  }
+
+
+  @Test public void failure() throws InterruptedException {
+    TestSubscriber<Void> subscriber = new TestSubscriber<>();
+    service.completable().subscribe(subscriber);
+    assertFalse(subscriber.awaitValueCount(1, 1, SECONDS));
+
+    server.enqueue(new MockResponse().setSocketPolicy(DISCONNECT_AFTER_REQUEST));
+    subscriber.awaitTerminalEvent(1, SECONDS);
+    subscriber.assertError(IOException.class);
+  }
+
+  @Test public void throwingInOnCompleteDeliveredToPlugin() throws InterruptedException {
+    server.enqueue(new MockResponse());
+
+    final CountDownLatch latch = new CountDownLatch(1);
+    final AtomicReference<Throwable> errorRef = new AtomicReference<>();
+    RxJavaPlugins.getInstance().registerErrorHandler(new RxJavaErrorHandler() {
+      @Override public void handleError(Throwable throwable) {
+        if (!errorRef.compareAndSet(null, throwable)) {
+          throw Exceptions.propagate(throwable); // Don't swallow secondary errors!
+        }
+        latch.countDown();
+      }
+    });
+
+    final TestSubscriber<Void> subscriber = new TestSubscriber<>();
+    final RuntimeException e = new RuntimeException();
+    service.completable().unsafeSubscribe(new AsyncCompletableSubscriber() {
+      @Override public void onCompleted() {
+        throw e;
+      }
+
+      @Override public void onError(Throwable t) {
+        subscriber.onError(t);
+      }
+    });
+
+    latch.await(1, SECONDS);
+    assertThat(errorRef.get()).isSameAs(e);
+  }
+
+  @Test public void bodyThrowingInOnErrorDeliveredToPlugin() throws InterruptedException {
+    server.enqueue(new MockResponse().setResponseCode(404));
+
+    final CountDownLatch latch = new CountDownLatch(1);
+    final AtomicReference<Throwable> pluginRef = new AtomicReference<>();
+    RxJavaPlugins.getInstance().registerErrorHandler(new RxJavaErrorHandler() {
+      @Override public void handleError(Throwable throwable) {
+        if (!pluginRef.compareAndSet(null, throwable)) {
+          throw Exceptions.propagate(throwable); // Don't swallow secondary errors!
+        }
+        latch.countDown();
+      }
+    });
+
+    final TestSubscriber<Void> subscriber = new TestSubscriber<>();
+    final RuntimeException e = new RuntimeException();
+    final AtomicReference<Throwable> errorRef = new AtomicReference<>();
+    service.completable().unsafeSubscribe(new AsyncCompletableSubscriber() {
+      @Override public void onCompleted() {
+        subscriber.onCompleted();
+      }
+
+      @Override public void onError(Throwable t) {
+        errorRef.set(t);
+        throw e;
+      }
+    });
+
+    latch.await(1, SECONDS);
+    //noinspection ThrowableResultOfMethodCallIgnored
+    CompositeException composite = (CompositeException) pluginRef.get();
+    assertThat(composite.getExceptions()).containsExactly(errorRef.get(), e);
+  }
+}
