fixes #269 nngcat unreliable with ZeroTier transport

This does a few things.  First it closes a case where a dropped
message could prevent subsequent connection attempts from getting through.

Second, it changes the rate at which we retry, and the timeout, to be
a lot more aggressive when attempting to establish a connection.  We
retry every 500 ms, for up to 2 minutes, before giving up.  This gives
a lot more resilience in the face of message loss that is typical of
ZeroTier in some environments when first establishing communication.

Third, makes the values for the connection attempts *tunable*, so
that applications can adjust for different deployment scenarios.

Fourth, it includes the ability to get the UDP socket name.  This was
needed during some debug, and may be useful for a real UDP transport
later, so we're keeping it.

Finally, we added documentation for the above items.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/zt.c b/tests/zt.c
index fa662857..4009588a 100644
--- a/tests/zt.c
+++ b/tests/zt.c
@@ -103,7 +103,7 @@ check_props(nng_msg *msg)
 
 		z = sizeof(c);
 		c = 0;
-		So(nng_pipe_getopt(p, NNG_OPT_ZT_PING_COUNT, &c, &z) == 0);
+		So(nng_pipe_getopt(p, NNG_OPT_ZT_PING_TRIES, &c, &z) == 0);
 		So(c > 0 && c < 10); // actually 5...
 
 		t = 0;