Panic when returning Status with arbitrary Bytes in details

[dvshur]

Bug Report

Version

0.2.0

Platform

Mac OS Catalina

Description

I was trying to return a Status with details from an unary RPC call looking like this

Err(Status::with_details(
  Code::ResourceExhausted,
  "Too many requests",
  Bytes::from_static(b"hello"),
))

It panicked with an error:

thread 'tokio-runtime-worker' panicked at 'called `Result::unwrap()` on an `Err` value: Status { code: Internal, message: "Couldn\'t serialize non-text grpc status header" }', /Users/<usr>/.cargo/registry/src/github.com-1ecc6299db9ec823/tonic-0.2.0/src/server/grpc.rs:225:9

Upon discussing with @LucioFranco in Discord:

• This is probably due to this validation
• Since the bytes are going to a *-bin header, they should probably be base64-serialized according to spec.

[LucioFranco]

The test in #345 should reproduce but it seems to pass

[dvshur]

Bytes::from_static(&[1]) reproduce the bug.