We do not see the stack notifying POLLRDHUP on receiving FIN.

The following test timesout the poll:
ASSERT_THAT(shutdown(accepted.get(), SHUT_WR), SyscallSucceeds());
struct pollfd pfd = {
.fd = conn_fd.get(),
.events = POLLRDHUP,
};
constexpr int kTimeout = 10000;
int n = poll(&pfd, 1, kTimeout);
ASSERT_GE(n, 0) << strerror(errno);
ASSERT_EQ(n, 1);
ASSERT_EQ(pfd.revents, POLLRDHUP);