Handle non-int multichannel message IDs (dart-lang/stream_channel#80)

When running in wasm, a number in a `List` will be parsed as a `double`.
On the web the `as int` cast succeeds, but in dart2wasm it fails. Cast
to `num` and use `toInt()` to more reliably get an `int` value.
2 files changed
tree: b39e174525749f630caa25d9c3013a4fb14f5fb5
  1. pkgs/