[nicm]

yes, this sucks but i have never myself been able to find a reliable case where screen reacts any better than tmux (for example, both behave similarly with yes(1))

the c0-* stuff is poor (i'm tempted to remove it) but it is not an easy problem to solve, people want tmux to be fast, except when they don't. it's also tricky remotely where ssh and the network stack are buffering too