Downloads a file from the given URL and saves it to the given filename. Returns whether the download succeeded.

Options:

  show_progress: whether to show download progress. Default: false.
  logger: the logger to use. If not given, this function will log to STDERR.
  cacert: a CA certificate file to use for verifying SSL websites.
          The default is to use the download tool's down CA database.
  use_cache: Whether to copy the file from the download cache, if available.
             Default: false.
  connect_timeout: The maximum amount of time to spend on DNS lookup
                   and establishing the TCP connection. Set to nil to
                   disable this timeout. Default: 4.
  idle_timeout: The maximum idle read time. Set to nil to set this timeout
                to the default wget value, 900. Set to nil to disable this
                timeout. Default: 5.
  total_timeout: The maximum amount of time spent on the whole download
                 operation, including connection time. Only has effect on curl.
                 Set to nil to disable this timeout. Default: nil.