Flush the log file for each write

This allows the log file to function `sync`, whilst keeping the benefit of an `async` mount for everything else

Author: RealOrangeOne

runusb/__main__.py

@@ -346,8 +346,13 @@ def _log_output(self, pipe: IO[str]) -> None:
 
         This is done in a separate thread to avoid blocking the main thread.
         """
+        log_fileno = self.handler.stream.fileno()
+
         for line in iter(pipe.readline, ''):
             USERCODE_LOGGER.log(USERCODE_LEVEL, line.rstrip('\n'))
+
+            # Forcefully sync the file, regardless of how it was mounted
+            os.fsync(log_fileno)
         LOGGER.info('Process output finished')
 
     def _rotate_old_logs(self, log_dir: str) -> None: