'Transfer legal headers from an original client request to dictionary
that will be used as headers by the backend request
:param src_headers: A dictionary of the original client request headers
:param dst_headers: A dictionary of the backend request headers'

def transfer_headers(self, src_headers, dst_headers):

    st = self.server_type.lower()
    x_remove = ('x-remove-%s-meta-' % st)
    dst_headers.update(((k.lower().replace('-remove', '', 1), '') for k in src_headers if (k.lower().startswith(x_remove) or (k.lower() in self._x_remove_headers()))))
    dst_headers.update(((k.lower(), v) for (k, v) in src_headers.items() if ((k.lower() in self.pass_through_headers) or is_sys_or_user_meta(st, k))))
