In addition to the (build-)dependency on an old version of rust-crossbeam-queue, rust-tokio-process (build-)depends on version 0.1 of rust-futures. Upstream seems to have abandoned the crate, there was an alpha release supporting futures 0.2, but the code appears to have been removed from the tokio git repository.
There are no reverse dependencies in testing or unstable If there are no objections in a few weeks, I intend to file a removal request.
