Function usize_to_i64 

pub fn usize_to_i64(value: usize, value_name: &str) -> Result<i64>

Converts usize values such as Vec::len() or byte-slice lengths to i64.

This is infallible only on 32-bit platforms, but the fallible signature keeps call sites consistent with the other checked conversions.

Errors

Returns an error when value exceeds i64::MAX.