in src/states.js [371:381]
await getRandomBytes(32),
sessionId,
[
new SupportedVersionsExtension(null, VERSION_TLS_1_3),
new PreSharedKeyExtension(null, null, pskIndex),
]
));
// If the client sent a non-empty sessionId, the server *must* send a change-cipher-spec for b/w compat.
if (sessionId.byteLength > 0) {
await this.conn._sendChangeCipherSpec();
}