What is the meaning of filter plugin RecordTransformerFilter uses filter_stream?
<p>err message:</p>

<pre><code>fluent/event_router.rb:213:optimizable?: Filtering works with worse performance, because [Fluent::Plugin::RecordTransformerFilter] uses `#filter_stream` method.
</code></pre>

<p>I use <code>router.emit(tag, time, record)</code> in my plugin , and error occurs when I emit event,my conf section:</p>

<pre><code>&lt;filter info.type.abc&gt;
@type record_transformer
renew_record 
keep_keys foolish,barsaker,idiots,similiar,
&lt;/filter&gt;
</code></pre>