In Java lib, TAsyncClient does not reset ___error after exception was raised

Currently when an exception is thrown, serialized and de-serialized into async client (AsyncIface which in turn uses TAsyncClient), the ___error field is set:

onError

However after that there's no way to reset that ___error field even if the exception is handled by callback, resulting in that the client is no longer usable, because in:

onReady

method the ___error field is checked and refused to continue.

We should probably either:

• find a way to let clients or callers to reset the field, or
• document it clearly that call site should re-create the client from async client factory upon encountering an exception