Function seq_at_or_after 

pub fn seq_at_or_after(a: Wrapping<u32>, b: Wrapping<u32>) -> bool

Returns true if a comes after, or is at b in the sequence number space, relative to the maximum possible window size.

Please note this is not a connex binary relation; in other words, given two sequence numbers, it’s sometimes possible that seq_at_or_after(a, b) || seq_at_or_after(b, a) == false. This is why seq_after(a, b) can’t be defined as simply !seq_at_or_after(b, a).