Use the Rust toolchain via the DotSlash Windows shim
Use the Rust toolchain via the DotSlash Windows shim

Reviewed By: mzlee

Differential Revision: D22495160

fbshipit-source-id: 3d6240906dd086ccac6668d907074ec7ca86ebce

rsocket/rsocket-cpp,rsocket/rsocket-cpp,rsocket/rsocket-cpp,ReactiveSocket/reactivesocket-cpp,ReactiveSocket/reactivesocket-cpp,rsocket/rsocket-cpp,ReactiveSocket/reactivesocket-cpp