diff --git a/include/haproxy/stconn-t.h b/include/haproxy/stconn-t.h
index e2f13f1..4396b02 100644
--- a/include/haproxy/stconn-t.h
+++ b/include/haproxy/stconn-t.h
@@ -284,6 +284,10 @@
 
 	unsigned int flags;                  /* SC_FL_* */
 	unsigned int ioto;                   /* I/O activity timeout */
+	ssize_t room_needed;                 /* free space in the input buffer required to receive more data.
+					      *    -1   : the SC is waiting for room but not on a specific amount of data
+					      *    >= 0 : min free space required to progress. 0 means SC must be unblocked ASAP
+					      */
 	struct wait_event wait_event;        /* We're in a wait list */
 	struct sedesc *sedesc;               /* points to the stream endpoint descriptor */
 	enum obj_type *app;                  /* points to the applicative point (stream or check) */
diff --git a/src/stconn.c b/src/stconn.c
index 8458331..cb3d750 100644
--- a/src/stconn.c
+++ b/src/stconn.c
@@ -136,6 +136,7 @@
 	sc->flags = SC_FL_NONE;
 	sc->state = SC_ST_INI;
 	sc->ioto = TICK_ETERNITY;
+	sc->room_needed = 0;
 	sc->app = NULL;
 	sc->app_ops = NULL;
 	sc->src = NULL;