MINOR: connections/mux: Add the wait reason(s) to wait_list.

Add a new element to the wait_list, that let us know which event(s) we are
waiting on.
diff --git a/include/proto/connection.h b/include/proto/connection.h
index e4621cc..35b9dfe 100644
--- a/include/proto/connection.h
+++ b/include/proto/connection.h
@@ -601,6 +601,7 @@
 	LIST_INIT(&cs->wait_list.list);
 	LIST_INIT(&cs->send_wait_list);
 	cs->conn = conn;
+	cs->wait_list.wait_reason = 0;
 }
 
 /* Initializes all required fields for a new connection. Note that it does the
diff --git a/include/types/connection.h b/include/types/connection.h
index abe85a4..9a1ba96 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -44,9 +44,15 @@
 struct server;
 struct pipe;
 
+enum sub_event_type {
+	SUB_CAN_SEND        = 0x00000001,  /* Schedule the tasklet when we can send more */
+	SUB_CAN_RECV        = 0x00000002,  /* Schedule the tasklet when we can recv more */
+};
+
 struct wait_list {
 	struct tasklet *task;
 	struct list list;
+	int wait_reason;
 };
 
 /* A connection handle is how we differenciate two connections on the lower
@@ -90,9 +96,6 @@
 	CS_SHW_SILENT       = 1,           /* imminent close, don't notify peer */
 };
 
-enum sub_event_type {
-	SUB_CAN_SEND        = 0x00000001,  /* Schedule the tasklet when we can send more */
-};
 /* For each direction, we have a CO_FL_{SOCK,DATA}_<DIR>_ENA flag, which
  * indicates if read or write is desired in that direction for the respective
  * layers. The current status corresponding to the current layer being used is