def __init__(
        self,
        env: Environment,
        output_file: IO = None,
        resume: bool = False
    ):
        """
        :param resume: Should the download resume if partial download
                       already exists.

        :param output_file: The file to store response body in. If not
                            provided, it will be guessed from the response.

        :param progress_file: Where to report download progress.

        """
        self.finished = False
        self.status = DownloadStatus(env=env)
        self._output_file = output_file
        self._resume = resume
        self._resumed_from = 0

        :param resume: Should the download resume if partial download
                       already exists.

        :param output_file: The file to store response body in. If not
                            provided, it will be guessed from the response.

        :param progress_file: Where to report download progress.

        
httpie/downloads.py