Converting proto version of ResourceMetric to the TypeScript version

[madhusudancs]

We have a Typescript gRPC service (receiver) that receives a bunch of metrics from another service (sender) that cannot directly send metrics to our OTel collectors (runs on a separate network). These metrics sent over gRPC use these protos: https://github.com/open-telemetry/opentelemetry-proto/blob/v1.4.0/opentelemetry/proto/metrics/v1/metrics.proto#L56-L99

Because we read this in Typescript code that implements gRPC handlers (receiver) for service methods with request embedding the MetricsData, they are deserialized into Typescript types generated for the above protos. Now, in order to send this to the collector, in our receiver we are using the metrics exporter's export() method: https://github.com/open-telemetry/opentelemetry-js/blob/experimental/v0.54.2/experimental/packages/opentelemetry-exporter-metrics-otlp-http/src/OTLPMetricExporterBase.ts#L136-L141.

Unfortunately, this requires metrics to be a Typescript defined ResourceMetrics type that's not easily convertible from the proto version of ResourceMetrics. I see converters in the other direction in the transformer packages.

How do I convert this to the type that the exporter expects? Or is there another way that allows us to bypass this type conversion at all?