Add accessor to useEMS flag

conn.go

@@ -1729,3 +1729,7 @@ func (c *Conn) VerifyHostname(host string) error {
 	}
 	return c.peerCertificates[0].VerifyHostname(host)
 }
+
+func (con *Conn) UsedEMS() bool {
+	return con.useEMS
+}