+ enough so that they can all get received in one shoot.
+ * gras_datadesc_by_name and gras_msgtype_by_name: now raise an exception
+ if not found. Use the *_or_null() variant for the old semantic.
+ * In gras_msg_handle, do not discard messages without callback.
+ They are probably messages to be explicitly awaited later (ie, proofs of
+ mis-synchronization in userland since they are sent before being awaited)
+ No big deal usually.
+ * gras_socket_meas_send/recv: semantic changed!
+ The numerical arguments used to be (1) the total amount of data to send
+ and (2) msg_size. This was changed to (1) msg_size and (2) amount of
+ messages. This was need for the fool willing to send more than MAXINT
+ bytes on quite fat pipes.
+