Function find_pattern_difference 

pub fn find_pattern_difference(
    run1: &HostInputs,
    run2: &HostInputs,
) -> Option<PatternDifference>

The first open, in order, at which exactly one run found an identity it had not found at that path before while the other run found one it had, when that identity is a different host inode.

Returns None when either log is incomplete, when the patterns agree up to the first open whose path, thread or syscall number differs, when both runs found an unfamiliar identity at the same open, which no single run explains, or when the first such difference keeps the host inode.