PayPal\Api\VerifyWebhookSignature::setTransmissionSig PHP Method

    public function setTransmissionSig($transmission_sig)
    {
        $this->transmission_sig = $transmission_sig;
        return $this;
    }

* Just uncomment the below line to read the data from actual request.
*/
/** @var Array $headers */
//$headers = getallheaders();
/**
* In Documentions https://developer.paypal.com/docs/api/webhooks/#verify-webhook-signature_post 
* All header keys as UPPERCASE, but I recive the header key as the example array, First letter as UPPERCASE
*/
$headers = array_change_key_case($headers, CASE_UPPER);
$signatureVerification = new VerifyWebhookSignature();
$signatureVerification->setAuthAlgo($headers['PAYPAL-AUTH-ALGO']);
$signatureVerification->setTransmissionId($headers['PAYPAL-TRANSMISSION-ID']);
$signatureVerification->setCertUrl($headers['PAYPAL-CERT-URL']);
$signatureVerification->setWebhookId("9XL90610J3647323C");
// Note that the Webhook ID must be a currently valid Webhook that you created with your client ID/secret.
$signatureVerification->setTransmissionSig($headers['PAYPAL-TRANSMISSION-SIG']);
$signatureVerification->setTransmissionTime($headers['PAYPAL-TRANSMISSION-TIME']);
$webhookEvent = new WebhookEvent();
$webhookEvent->fromJson($requestBody);
$signatureVerification->setWebhookEvent($webhookEvent);
$request = clone $signatureVerification;
try {
    /** @var \PayPal\Api\VerifyWebhookSignatureResponse $output */
    $output = $signatureVerification->post($apiContext);
} catch (Exception $ex) {
    // NOTE: PLEASE DO NOT USE RESULTPRINTER CLASS IN YOUR ORIGINAL CODE. FOR SAMPLE ONLY
    ResultPrinter::printError("Validate Received Webhook Event", "WebhookEvent", null, $request->toJSON(), $ex);
    exit(1);
}
// NOTE: PLEASE DO NOT USE RESULTPRINTER CLASS IN YOUR ORIGINAL CODE. FOR SAMPLE ONLY
ResultPrinter::printResult("Validate Received Webhook Event", "WebhookEvent", $output->getVerificationStatus(), $request->toJSON(), $output);