Function grpc_trace_fn 

pub fn grpc_trace_fn<T>(request: &Request<T>) -> Span

Returns a trace_fn implementation for gRPC requests which adds open-telemetry information to the span.

Creates an info span following the open-telemetry standard: {service}/{method}. The span name is dynamically set using the HTTP path via the otel.name field. Additionally also pulls in remote tracing context which allows the server trace to be connected to the client’s origin trace.