CustomFCMTransport returns a FCMTransport.

GenerateFCMTokenProvider gets a valid token for FCM.

GetFCMHTTPClient returns an HttpClient able to performs requests setting a valid Authorization header.

GetTracingHeaders returns tracing headers computed from the given context.

Init see: https://opentelemetry.io/docs/go/getting-started/ If needed, start a new span: opentelemetry.GetTracer().Start(parentCtx, name, ..) See examples.

InitMetrics creates a new server on the port provided that exposes metrics.

FCMTransport defines a httpTransport with a custom RoundTripper.

SampleByRatio implements Sampler interface: https://pkg.go.dev/go.opentelemetry.io/otel/sdk/trace#Sampler Be aware this will also check for an attribute named FlagSkip.