docs: def remote_file_size(self, remote_cmd="", remote_file=None):
          """Get the file size of the remote file."""
          if remote_file is None:
              if self.direction == "put":
                  remote_file = self.dest_file
              elif self.direction == "get":
                  remote_file = self.source_file
          if not remote_cmd:
              remote_cmd = "dir {}/{}".format(self.file_system, remote_file)
          remote_out = self.ssh_ctl_chan.send_command(remote_cmd)
          # Strip out "Directory of flash:/filename line
          remote_out = re.split(r"Directory of .*", remote_out)
          remote_out = "".join(remote_out)
          # Match line containing file name
          escape_file_name = re.escape(remote_file)
          pattern = r".*({}).*".format(escape_file_name)
          match = re.search(pattern, remote_out)
          if match:
              line = match.group(0)
              # Format will be 26  -rw-   6738  Jul 30 2016 19:49:50 -07:00  filename
              file_size = line.split()[2]
          if "Error opening" in remote_out or "No such file or directory" in remote_out:
              raise IOError("Unable to find file on remote system")
          else:
              return int(file_size)