This SDK uses an asynchronous programming model in which operations are triggered and then run in the background until they are completed. Upon successful or unsuccessful completion, the operation invokes a callback/webhook function, which is to be provided by the developer, and returns Verification Response objects that include the results of the given operation.The callback/webhook function should handle the response in an appropriate manner, as determined by the application. Production callback/webhooks must be delivered to secure endpoints. For more information about Callbacks / Webhooks, click here. Polling can be used to actively retrieve timely responses as an alternative or along-side callback/webhook function. For more information on Polling, click here.