Constant ALIGNED_TIMESTAMP_OPTION_LENGTH 

pub const ALIGNED_TIMESTAMP_OPTION_LENGTH: usize = _; // 12usize

Per RFC 7323 Section 3.2, the TCP Timestamp option has a length of 10 bytes: +—––+—––+———————+———————+ |Kind=8 | 10 | TS Value (TSval) |TS Echo Reply (TSecr)| +—––+—––+———————+———————+ 1 1 4 4

However, once aligned, it will occupy 12 bytes.