docs: def write_to_remote(self, filepath_from, filepath_to, mtime_dt=None):
          """Open a local file and write it remotely."""
  
          self.__log.debug("Writing L[%s] -> R[%s]." % (filepath_from, 
                                                        filepath_to))
  
          with open(filepath_from, 'rb') as file_from:
              with SftpFile(self, filepath_to, 'w') as sf_to:
                  while 1:
                      part = file_from.read(MAX_MIRROR_WRITE_CHUNK_SIZE)
                      sf_to.write(part)
  
                      if len(part) < MAX_MIRROR_WRITE_CHUNK_SIZE:
                          break
  
          if mtime_dt is None:
              mtime_dt = datetime.now()
  
          self.utimes_dt(filepath_to, mtime_dt, mtime_dt)