rsocket | Fix building with `-Wrange-loop-analysis` on
rsocket | Fix building with `-Wrange-loop-analysis` on

Summary: This fixes a warning when `-Wrange-loop-analysis` is on which is default under clang 10.

Reviewed By: alexmalyshev

Differential Revision: D22205864

fbshipit-source-id: bf7f9594bb14fcaee3f17da2a55d5f68f42b870f

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