Reproducing issuing autometrics along with async-trait.

Instructions

Run in sequence:

• Terminal 1: Server

  $ cargo run
  Compiling autometrics-async-trait-repro v0.1.0
   Finished dev [unoptimized + debuginfo] target(s) in 1.75s
    Running `target/debug/autometrics-async-trait-repro`
  

• Terminal 2: Client

  $ cargo run -- client
  Compiling autometrics-async-trait-repro v0.1.0
   Finished dev [unoptimized + debuginfo] target(s) in 0.77s
    Running `target/debug/autometrics-async-trait-repro client`
  RESPONSE=Ok(Response { metadata: MetadataMap { headers: {"content-type": "application/grpc", "date": "Thu, 30 Nov 2023 16:57:35 GMT", "grpc-status": "0"} }, message: HelloReply { message: "Hello Tonic!" }, extensions: Extensions })
  RESPONSE=Err(Status { code: Internal, message: "error!", metadata: MetadataMap { headers: {"content-type": "application/grpc", "date": "Thu, 30 Nov 2023 16:57:35 GMT", "content-length": "0"} }, source: None })
  RESPONSE=Ok(Response { metadata: MetadataMap { headers: {"content-type": "application/grpc", "date": "Thu, 30 Nov 2023 16:57:35 GMT", "grpc-status": "0"} }, message: HelloReply { message: "Hello Tonic!" }, extensions: Extensions })
  RESPONSE=Err(Status { code: Internal, message: "error!", metadata: MetadataMap { headers: {"content-type": "application/grpc", "date": "Thu, 30 Nov 2023 16:57:35 GMT", "content-length": "0"} }, source: None })
  
  

• Terminal 3: Query

  $ curl localhost:3000/metrics | rg 'result='
  function_calls_total{function="MyGreeter::say_hello",module="autometrics_async_trait_repro",service_name="autometrics",caller_function="",caller_module="",result="",ok="",error="",objective_name="",objective_percentile=""} 4