message: build: Add tokio-util for CancellationTokens
  Should've gone in with thread cancelling commit. Ah well.
diff: @@ -69,6 +69,7 @@ wasm-bindgen = { version = "0.2.73", optional = true }
  tokio = { version = "1.4.0", features = ["sync"] }
  async-stream = "0.3.0"
  prost = "0.7.0"
  +tokio-util = "0.6.5"
  [target.'cfg(windows)'.dependencies]
  rusty-xinput = "1.2.0"
  