Event is used to know the state of the call on Plivo Cloud. Modifications on alive call will throw different events to let the user application know about the progress of the call.
Plivo will send one of the following values under the
The call has been answered and is currently in progress. Calls under this status can be explicitly terminated using the Hangup API
The call has been transfered using the Transfer API. This event is sent to target URL of theXML you return from the Transfer URL.
The call has been redirected using the Redirect XML element
This event is generated when the machine_detection parameter is used in the Outbound Call API request. The event is sent to the machine_detection URL.