deriveSrtpKeyingMaterial

SrtpKeyingMaterial deriveSrtpKeyingMaterial(const(ubyte)[]  masterSecret,
       const(ubyte)[]  clientRandom,  const(ubyte)[]  serverRandom,
       SrtpProfile profile)

Derives SRTP keying material from DTLS handshake secrets.

Implements RFC 5764 §4.2 key derivation using the TLS 1.2 PRF (or HKDF for TLS 1.3 connections, though DTLS-SRTP is typically used with DTLS 1.2).

Parameters

`masterSecret`	The DTLS master secret bytes.
`clientRandom`	The client random from the handshake.
`serverRandom`	The server random from the handshake.
`profile`	The negotiated SRTP profile.

Returns

SRTP keying material for both directions.