tracing

type Span interface {
	// End completes the Span. The Span is considered complete and ready to be
	// delivered through the rest of the telemetry pipeline after this method
	// is called. Therefore, updates to the Span are not allowed after this
	// method has been called.
	End()
}

type Tracer interface {
	// Start creates a span and a context.Context containing the newly-created
	// span.
	//
	// If the context.Context provided in `ctx` contains a Span then the
	// newly-created Span will be a child of that span, otherwise it will be a
	// root span.
	//
	// Any Span that is created MUST also be ended. This is the responsibility
	// of the user. Implementations of this API may leak memory or other
	// resources if Spans are not ended.
	Start(context.Context, string, string) (context.Context, Span)
}