Tls13KeySchedule.deriveSecret

private

ubyte[] deriveSecret(const(ubyte)[]  secret,  string label,
          const(ubyte)[]  transcriptHash)

Derives a secret using HKDF-Expand-Label per RFC 8446 §7.1.

`secret`	The base secret.
`label`	The label string (without "tls13 ").
`transcriptHash`	The hash of the handshake transcript.

The derived secret.