allocates inbound or outbound connection runs init_accepted or init_outbound updates stats creates socket_connection */

deletes link to io_conn deletes link to target aborts pending queries updates stats */

* MD5 final digest */

* MD5 context setup */

may invoke mpq_push() to discard new empty block

may invoke mpq_alloc_block (which recursively invokes mpq_pop) or mpq_push() (without needing to hold hazard pointer) to deal with blocks */

may invoke mpq_pop()/mpq_push() if allow_recursion=1

must be called with mutex held */ mode = 0 -- lookup, mode = 1 -- insert, mode = -1 -- delete */

must be called with mutex held */ mode = 0 -- lookup, mode = 1 -- insert, mode = -1 -- delete */

after this function non-empty raw message raw should have following properties: refcnt of all msg_parts in raw is 1 raw->first_offset = raw->first->of

result: 1 = OK, 0 = already done, -1 = error

after this function non-empty raw message raw should have following properties: raw->first_offset == raw->first->offset