ASIO includes a useful feature that allows custom log hooks to be compiled in to track handler events such as creation, completion invocation start, and invocation end.

The default implementation logs to std::cout, but there is a mechanism to allow custom hooks to be used by defining some macros (see handler_tracking.hpp).

We should define ASIO_CUSTOM_HANDLER_TRACKING in debug builds, add log hooks at some verbosity level > 1, and probably add a new log component as it will be very, very chatty.