public function get_delivery_signature( $payload ) {

		/**
		 * Allow overriding of signature generation.
		 *
		 * @since 1.0.0-beta.1
		 *
		 * @param string $signature Custom signature. Return a string to replace the default signature.
		 * @param string $payload JSON-encoded body to be delivered.
		 * @param int $id Webhook id.
		 */
		$signature = apply_filters( 'llms_rest_webhook_signature_pre', null, $payload, $this->get( 'id' ) );
		if ( $signature && is_string( $signature ) ) {
			return $signature;
		}

		/**
		 * Customize the hash algorithm used to generate the webhook delivery signature.
		 *
		 * @since 1.0.0-beta.1
		 *
		 * @param string $algo Hash algorithm. Defaults to 'sha256'. List of supported algorithms available at https://www.php.net/manual/en/function.hash-hmac-algos.php.
		 * @param string $payload JSON-encoded body to be delivered.
		 * @param int $id Webhook ID.
		 */
		$hash_algo = apply_filters( 'llms_rest_webhook_hash_algorithm', 'sha256', $payload, $this->get( 'id' ) );
		$ts        = llms_current_time( 'timestamp' );
		$message   = $ts . '.' . $payload;
		$hash      = hash_hmac( $hash_algo, $message, $this->get( 'secret' ) );

		return sprintf( 't=%1$d,v1=%2$s', $ts, $hash );

	}