Endpoint with NoContent status cannot succeed on client side

[minedeljkovic]

Describe the bug
Using endpoint defined with NoContent status fails with Malformed request body failed to decode: Non-empty body cannot be decoded as Unit

To Reproduce

val unitEndpoint = Endpoint((Method.GET / "")).out[Unit](Status.NoContent)
val unitRoute = unitEndpoint.implement(_ => ZIO.unit)
ZIO
  .scoped(
    for {
      _ <- Server.serve(unitRoute).forkScoped
      exec <- ZIO.serviceWith[Client] { client =>
        EndpointExecutor(client, EndpointLocator.fromURL(URL.decode("http://localhost:8080").toOption.get))
      }
      result <- exec(unitEndpoint(()))
    } yield {
      result
    }
  )
  .provide(Server.live, ZLayer.succeed(Server.Config.default), Client.default)

// res0: Exit[Throwable, Unit] = Failure(Die(zio.http.codec.HttpCodecError$MalformedBody: Malformed request body failed to decode: Non-empty body cannot be decoded as Unit,Stack trace for thread "zio-fiber-":
// ))

Expected behaviour
Client request should succeed with unit value.

Desktop (please complete the following information):

• OS: Linux

Additional context
Using Ok instead of NoContent status succeeds:

val unitEndpoint = Endpoint((Method.GET / "")).out[Unit](Status.Ok)
val unitRoute = unitEndpoint.implement(_ => ZIO.unit)
ZIO
  .scoped(
    for {
      _ <- Server.serve(unitRoute).forkScoped
      exec <- ZIO.serviceWith[Client] { client =>
        EndpointExecutor(client, EndpointLocator.fromURL(URL.decode("http://localhost:8080").toOption.get))
      }
      result <- exec(unitEndpoint(()))
    } yield {
      result
    }
  )
  .provide(Server.live, ZLayer.succeed(Server.Config.default), Client.default)

// res0: Exit[Throwable, Unit] = Success(())

From what I found, the codec on client side depends on the existence of content-length header to exist to be able to decode Unit, while otoh server (rightfully, according to HTTP spec) leaves this header out in the NoContent case.
Relevant code:

• zio-http/zio-http/jvm/src/main/scala/zio/http/netty/NettyResponse.scala

  Lines 50 to 55 in 6c99669

  	val headers = Conversions.headersFromNetty(jRes.headers())
  	val knownContentLength = headers.get(Header.ContentLength).map(_.length)
  	if (knownContentLength.contains(0L)) {
  	onComplete.unsafe.done(Exit.succeed(ChannelState.forStatus(status)))
  	Response(status, headers, Body.empty)

• zio-http/zio-http/shared/src/main/scala/zio/http/codec/internal/BodyCodec.scala

  Lines 134 to 136 in 6c99669

  	case Right((_, BinaryCodecWithSchema(_, schema))) if schema == Schema[Unit] =>
  	if (body.isEmpty) Exit.unit.asInstanceOf[IO[Throwable, A]]
  	else ZIO.fail(HttpCodecError.CustomError("InvalidBody", "Non-empty body cannot be decoded as Unit"))

[minedeljkovic]

One workaround I found was using HttpCodec.empty like so:

val unitEndpoint = Endpoint((Method.GET / "")).outCodec(HttpCodec.empty ++ StatusCodec.status(Status.NoContent))

Would this be an idiomatic way to define a NoContent endpoint?

Although, previous definition breaks the OpenAPI gen (maybe a sepparate issue?), so I ended up with something like this:

val unitEndpoint = Endpoint((Method.GET / "")).outCodec((HttpCodec.empty | HttpCodec.content[Unit]) ++ StatusCodec.status(Status.NoContent))