Discrepancy between as_nanos API and from_nanos API

[mlej8]

The as_nanos API in https://doc.rust-lang.org/src/core/time.rs.html#462 returns u128, however the from_nanos API https://doc.rust-lang.org/src/core/time.rs.html#276 only accepts u64. Can we make it u128 so that it is consistent ?

[Noratrieb]

Sadly not, as that would be a breaking change.

[jyn514]

I'm going to close this since we can't change the API here.