byte[] exportKeyingMaterial(String label, byte[] context, int length) throws SSLException {
        if (label == null) {
            throw new NullPointerException("Label is null");
        }
        byte[] labelBytes = label.getBytes(StandardCharsets.US_ASCII);
        return NativeCrypto.SSL_export_keying_material(ssl, this, labelBytes, context, length);
    }
A utility wrapper that abstracts operations on the underlying native SSL instance.
common/src/main/java/org/conscrypt/NativeSsl.java