Add annotation to leaks (use write instead of printf).
Moved send buffers to connection.
Moved async connection write handler to connection.
Added error callback for write errors.
Check if send buffer callback is null.
Use default connection write handler in echo server.
Implemented cx_strndup.
Moved queue implementation to list module.
Use common synchronized logging method for all debug and logging macros.
Encapsulate multiple statements in block to avoid errors with
missing brackets in statements.
Surround debug statements with brackets.