pub(crate) fn usize_to_u64(v: usize) -> u64Expand description
Converts usize to u64 without using as.
This is needed for example to convert in-memory buffer sizes to u64 type used for counting all the bytes written.
On 32-bit systems it is possible to have files larger than 4 GiB or write more than 4 GiB to network connection, in which case we need a 64-bit total counter, but use 32-bit usize for buffer sizes.
This can only break if usize has more than 64 bits and this is not the case as of 2025 and is unlikely to change for general purpose computers. See https://github.com/rust-lang/rust/issues/30495 and https://users.rust-lang.org/t/cant-convert-usize-to-u64/6243 and https://github.com/rust-lang/rust/issues/106050.