As R. Du Toit pointed out on the TLS mailing list, "Mechanism #1 requires 0-RTT support, but the middlebox would not be violating the TLS 1.3 specification by not implementing 0-RTT. " A middle box that blocks 0-RTT would effectively disrupts the "0-RTT tunneling" mechanism.
As R. Du Toit pointed out on the TLS mailing list, "Mechanism #1 requires 0-RTT support, but the middlebox would not be violating the TLS 1.3 specification by not implementing 0-RTT. " A middle box that blocks 0-RTT would effectively disrupts the "0-RTT tunneling" mechanism.