private static AbstractConscryptSocket toConscrypt(SSLSocket socket) {
        if (!isConscrypt(socket)) {
            throw new IllegalArgumentException(
                    "Not a conscrypt socket: " + socket.getClass().getName());
        }
        return (AbstractConscryptSocket) socket;
    }
Indicates whether the given {@link SSLSocket} was created by this distribution of Conscrypt.
common/src/main/java/org/conscrypt/Conscrypt.java