proposition: Lemma itree_eta : forall (t : itree E R), t ≈ go (observe t).
proof: Proof. intros. rewrite <- ITree.Eq.Eqit.itree_eta. reflexivity. Qed.
imports: Coq(Setoid Morphisms) ITree(Eq.Shallow) ITree.Core.ITreeDefinition ITree.Basics.Basics ITree.Indexed.Sum ITree.Interp.Interp ITree.Interp.Recursion ITree(Eq.Eqit Eq.UpToTaus Interp.InterpFacts Interp.RecursionFacts)