Function u64_step 

pub const fn u64_step(radix: u32) -> usize

Available on crate features parse-floats or parse-integers or write-floats or write-integers only.

Calculate the number of digits that can be processed without overflowing a u64. Helper function since this is used for 128-bit division.

This is an alias for min_step with bits == 64 and is_signed == false.