server-transports example does not compile

[tertsdiepraam]

The server-transports example should compile with

cargo build --example server-transports --features="net unstable-server-transport"

but only compiles with 2 additional dev-dependencies and another feature flag:

cargo add --dev tracing_subscriber -F env-filter
cargo add --dev tokio_stream
cargo build --example server-transports --features="net unstable-server-transport unstable-client-transport"

[ximon18]

FYI #432 fixes a similar issue in the serve-zone example.

[tertsdiepraam]

@ximon18 this was fixed by #432 as well right?