'Gets back all response headers.'

def get_all_response_headers(self):

    bstr_headers = c_void_p()
    _WinHttpRequest._GetAllResponseHeaders(self, byref(bstr_headers))
    bstr_headers = ctypes.cast(bstr_headers, c_wchar_p)
    headers = bstr_headers.value
    _SysFreeString(bstr_headers)
    return headers
