Application components running at various sites within a
        replication group can now use the Replication Manager's existing
        TCP/IP communications infrastructure to send and process messages
        among themselves, using the DB_CHANNEL handle.
        DB_ENV->repmgr_channel() is used to create the
        DB_CHANNEL handle.  DB_CHANNEL->send_msg() and
        DB_CHANNEL->send_request() are used to send sychronous and
        asychronous messages that are handled by the function set by
        DB_ENV->repmgr_msg_dispatch().  DB_CHANNEL->set_timeout() is used to
        configure channel time out, and DB_CHANNEL->close() closes the
        channel and frees resources held by it.