docs: def send(self, targetPath, parent, diff, showProgress=True, allowDryRun=True):
          """ Return context manager for stream to send a (incremental) snapshot. """
          if parent is not None:
              cmd = ["btrfs", "send", "-p", parent, targetPath]
          else:
              cmd = ["btrfs", "send", targetPath]
  
          if Store.skipDryRun(logger, self.dryrun and allowDryRun)("Command: %s", cmd):
              return None
  
          process = subprocess.Popen(
              cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=DEVNULL)
          _makeNice(process)
  
          return _Reader(process, process.stdout, targetPath, diff, showProgress)