core2 support #57
Description
Unfortunately, core doesn't have read/write traits so it's impossible to the "io" module is disabled when std is unavailable. Would you be amenable to optional (i.e., behind a "core2" feature flag) core2 feature to make it possible to use the "io" module without the standard library?
This would let us avoid recreating a read_u64 function in https://github.com/multiformats/rust-multihash/pull/146/files#diff-ed0fff016e18f897bd0f62ca08bfdfe35008320d5c1831bcf6728551f3ec0a39R308.