Implementation of AMP worker commands, and main executable 
entry point for the workers.
| Present Since | 12.3 | |
| Class | WorkerLogObserver | A log observer that forward its output to a AMPprotocol. | 
| Function | main | Main function to be run if __name__ == "__main__". | 
| Function | _setupPath | Override sys.pathwith what the parent passed in 
TRIAL_PYTHONPATH. |