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.