libtmux::kDefaultRetainedReplyBytes

A subprocess ends and gives its memory back; a connection does not, so the bound has to be in the decoder rather than in whatever reads it afterwards. The reply bound is the subprocess transport's capture limit, so the same call costs the same memory over either transport. The line bound has no subprocess equivalent: it is the point past which an unterminated line is evidence of a broken stream rather than a large answer.