Return key-value pairs for the list_time_series API call.

        :type headers_only: bool
        :param headers_only:
             Whether to omit the point data from the
             :class:`~google.cloud.monitoring_v3.types.TimeSeries` objects.

        :type page_size: int
        :param page_size:
            (Optional) The maximum number of points in each page of results
            from this request. Non-positive values are ignored. Defaults
            to a sensible value set by the API.

def _build_query_params(self, headers_only=False, page_size=None):
        """Return key-value pairs for the list_time_series API call.

        :type headers_only: bool
        :param headers_only:
             Whether to omit the point data from the
             :class:`~google.cloud.monitoring_v3.types.TimeSeries` objects.

        :type page_size: int
        :param page_size:
            (Optional) The maximum number of points in each page of results
            from this request. Non-positive values are ignored. Defaults
            to a sensible value set by the API.
        """
        params = {"name": self._project_path, "filter_": self.filter}

        params["interval"] = types.TimeInterval()
        params["interval"].end_time.FromDatetime(self._end_time)
        if self._start_time:
            params["interval"].start_time.FromDatetime(self._start_time)

        if (
            self._per_series_aligner
            or self._alignment_period_seconds
            or self._cross_series_reducer
            or self._group_by_fields
        ):
            params["aggregation"] = types.Aggregation(
                per_series_aligner=self._per_series_aligner,
                cross_series_reducer=self._cross_series_reducer,
                group_by_fields=self._group_by_fields,
                alignment_period={"seconds": self._alignment_period_seconds},
            )

        if headers_only:
            params["view"] = enums.ListTimeSeriesRequest.TimeSeriesView.HEADERS
        else:
            params["view"] = enums.ListTimeSeriesRequest.TimeSeriesView.FULL

        if page_size is not None:
            params["page_size"] = page_size

        return params