metadataUnsafe() is faster than metadata() because it
directly returns the array which comes from $(ZMQREF zmq_msg_gets()),
whereas the latter returns a freshly GC-allocated copy of it. However,
the array returned by metadataUnsafe() is owned by the underlying
$(ZMQ) message and gets destroyed along with it, so care must be
taken when using this function.
Gets message _metadata.
metadataUnsafe() is faster than metadata() because it directly returns the array which comes from $(ZMQREF zmq_msg_gets()), whereas the latter returns a freshly GC-allocated copy of it. However, the array returned by metadataUnsafe() is owned by the underlying $(ZMQ) message and gets destroyed along with it, so care must be taken when using this function.