Tweak spec test because pymongo unpins cursors eagerly after errors.
Tweak spec test for PoolClearedEvent ordering when MongoDB handshake fails (see DRIVERS-1785).
Only skip killCursors for some error codes.
Rely on SDAM error handling to close the connection after a state change error.
Add service_id to various events.
Retain reference to pinned sockets to prevent premptive closure by CPython's cyclic GC.
Move exhaust getMore out of Cursor.
Move cursor command response decoding into Server so that all command
listener events can be published in the same location.
Use _OpReply class instead of passing bytes around.
Remove unnecessary operation argument to receive message.
Move _first_batch to message.py to avoid circular import.
This commit adds support for monitoring queries and getMore
operations, including getMore operations for command cursors
(e.g. aggregate cursor getMore). It also fixes a bug in duration
calculation.
