Add read_exact_at
and write_all_at
to WASI's FileExt
#74076
Merged
bors merged 2 commits intorust-lang:master from sunfishcode:wasi-fileext-newmethodsJul 11, 2020
+137-4
read_exact_at
and write_all_at
to WASI's FileExt
#74076