+# If $mismatch_only is set, only non-matching responses will
+# be echoed.
+#
+# If $success_or_failure is set, the meaning of the arguments is
+# changed as follows:
+# $2: A string to search for in the response; if found, this indicates
+# success and ${QEMU_STATUS[$1]} is set to 0.
+# $3: A string to search for in the response; if found, this indicates
+# failure and the test is either aborted (if $qemu_error_no_exit
+# is not set) or ${QEMU_STATUS[$1]} is set to -1 (otherwise).
+_timed_wait_for()