+/* Extension context codes */
+#define EXT_DTLS_ONLY 0x01
+#define EXT_CLIENT_HELLO 0x02
+/* Really means TLS1.2 or below */
+#define EXT_TLS1_2_SERVER_HELLO 0x04
+#define EXT_TLS1_3_SERVER_HELLO 0x08
+#define EXT_TLS1_3_ENCRYPTED_EXTENSIONS 0x10
+#define EXT_TLS1_3_HELLO_RETRY_REQUEST 0x20
+#define EXT_TLS1_3_CERTIFICATE 0x40
+#define EXT_TLS1_3_NEW_SESSION_TICKET 0x80
+