i=365:---
parent 3980: continue
kid=1 3980 before require
parent 3980: continue
parent 3980: waiting for join
kid=2 3980 before require
kid=1 3980 after require
parent 3980: thread exited
parent 3980: waiting for join
kid=2 3980 after require
parent 3980: thread exited
i=366:---
parent 3980: continue
kid=1 3980 before require
parent 3980: continue
parent 3980: waiting for join
kid=2 3980 before require