+&proto_start
+unsigned char* rmr_get_xact( rmr_mbuf_t* mbuf, unsigned char* dest );
+&proto_end
+The bytes from the &ital(transaction) field in the message buffer are copied to the &ital(dest) buffer
+provided by the application.
+The full field of &cw(RMR_MAX_MEID) bytes are copied; the caller must ensure that &ital(dest)
+is large enough.
+If the destination buffer pointer passed in is a nil pointer, the function will allocate a buffer
+and return a pointer, which the caller is expected to free, to the buffer.
+