idle_timeout = max(3*PTO, TP.idle_timeout), skip draining period

draft-ietf-quic-transport.md

@@ -2276,9 +2276,10 @@ source address.
 
 ## Idle Timeout {#idle-timeout}
 
-If the idle timeout is enabled, a connection that remains idle for longer than
-the advertised idle timeout (see {{transport-parameter-definitions}}) is closed.
-A connection enters the draining state when the idle timeout expires.
+If the idle timeout is enabled, a connection is closed when it remains idle for
+longer than the larger of the advertised idle timeout (see
+{{transport-parameter-definitions}}) or three times the current Probe Timeout
+(PTO).  The connection state is discarded immediately when the timeout expires.
 
 Each endpoint advertises its own idle timeout to its peer.  An enpdpoint
 restarts any timer it maintains when a packet from its peer is received and