`BoxedStream` is private when the stream feature is disabled

[Berrysoft]

It would be convenient to make BoxedStream always public.

[bdbai]

From the API interface's perspective, it makes little sense to provide an BoxedStream with streaming features off. As you can see in our backend implementations, there is no need to reference the BoxedStream when streaming is disabled. Would you like to provide more context on why it's needed?

[Berrysoft]

I'm writing my cyper backend for nyquest. It needs BoxedStream for code simplicity.

[bdbai]

@Berrysoft Could you elaborate more on how exposing type BoxedStream = Infallible would help? Based on the nyquest-backend-reqwest implementation which encapsulates reqwest and supposedly having a similar API interface as cyper, I really could not visualize how it would be useful.

[Berrysoft]

Well, I tried again and succeeded without referencing BoxedStream directly. However, I do think it will simplify the usage if BoxedStream is exposed no matter the stream feature is enabled.