higher-order future compile error when wrapping AsyncProtocol into another future

[35359595]

In this repo is minimal code to reproduce the issue: https://github.com/35359595/mpecdsa-future-error

There's a know issue with the compiler described here: rust-lang/rust#102211 (comment)

In general, some internal future[s] of AsyncProtocol::run() have to be .boxed(). Please take a look.