server: introduce dispatcher

used for main_dispatcher only in this patch.

Dispatcher is meant to be used for Main<->any low frequency messages.

It's interface is meant to include the red_dispatcher usage:
 fixed size messages per message type
 some messages require an ack

Some methods are added to be used by RedDispatcher later:
 dispatcher_handle_read - to be called directly by RedDispatcher epoll
  based loop
 dispatcher_set_opaque - to be set from red_worker pthread
 dispatcher_init - allow NULL core as used by red_worker

Read and Write behavior:
 Sender: blocking write, blocking read for ack (if any).
 Reader: poll for any data, if such then blocking read for a
 message_type and following message. repeat until poll returns
 with no pending data to read.

FDO Bugzilla: 42463

0 files changed, 0 insertions, 0 deletions