The np_expect_match() function now returns one of three possible states
instead of just TRUE or FALSE:
- NP_MATCH_SUCCESS
- NP_MATCH_FAILURE
- NP_MATCH_RETRY
The NP_MATCH_RETRY state indicates that matching might succeed if
np_expect_match() is called with a longer input string. This allows
check_tcp to decide whether it makes sense to wait for additional data
from the server.