Informed by the discussion in the bug and the code in 'that other branch'
the fix was clear. Just set a flag if we start handling a write, and
use that flag to guard the long write complete call.
* Replaced ARDUINO_VARIANT with const char
* Fixed missing return value
* Added quotes around defined value in macro (Issue #2193)
* Change logging from Error to Verbose when not found and default available
* Move Enter and Exit logging to Verbose Level
* Refactored LOG_X() into log_x()