UIMA AS uses one instance of a Serializer object

There is a single instance of a Deserializer object processing incoming CASes and also a single instance of a Serializer object processing outgoing CASes. This may bottleneck UIMA AS Service when handling large CASes and multiple threads are processing incoming and outgoing CASes. It would be more efficient to create and dedicate an instance of a Serializer/Deserializer to each processing thread so that multiple CASes cas be serialized/deserialized at the same time.