Missing CollectAll() / ScrapeHandler.ProcessScrapeRequest equivalent

We have been using the CollectAll() to manually process and expose the metrics through our own endpoint.

In 3.0 we are unable to do so. Would it be possible to expose

                                using (var serializer = new TextSerializer(delegate
                                    {
                                        response.ContentType = PrometheusConstants.ExporterContentType;
                                        response.StatusCode = 200;
                                        return response.OutputStream;
                                    }, leaveOpen: false))
                                {
                                    _registry.CollectAndSerialize(serializer);
                                }

as a public helper method?

We are not going to ever use MetricServer and all related methods are internal at this point.

[sandersaares]

I have added CollectorRegistry.CollectAndExportAsText(Stream) to support metric data export via arbitrary custom endpoints.

You can parse the text document and perform any custom manipulation you wish, for extra custom scenarios, before export.

I will publish this as preview version later today, after going through other open issues, and a stable version next week. If you have any more feedback for me on this point, please feel free to share.

[connor4312]

Awesome thank you!