I'm pretty sure 'a read() of those bytes' (by emacs) is one part of a proccess of sending output to the
device. Emacs is 'the device' here and terminal line can not be closed and disconnected until all data
is sent. There should be no chance for the application to exit until the output is 'sent to the device'
hence no chance for the kernel to thow SIGCHLD.
It's not a pipe nor stream, it's an intaractive tty/pty.