def chunked?
    return false unless @header['transfer-encoding']
    field = self['Transfer-Encoding']
    (/(?:\A|[^\-\w])chunked(?![\-\w])/i =~ field) ? true : false
  end
Returns "true" if the "transfer-encoding" header is present and
set to "chunked".  This is an HTTP/1.1 feature, allowing the
the content to be sent in "chunks" without at the outset
stating the entire content length.