Function parse_size 

pub fn parse_size(input: &str) -> Result<u64>

Parse a human-readable size string into a byte count.

Accepts:

• Plain numbers: 1024 → 1024 bytes
• SI: K, M, G, T (1000-based)
• Binary: Ki, Mi, Gi, Ti (1024-based)
• With an optional trailing B (e.g. 1Gi, 1GiB)
• Case-insensitive; whitespace between digits and unit is ignored