The maximum time before which the worker processing this task must report progress by calling RecordActivityTaskHeartbeat. If the
            timeout is exceeded, the activity task is automatically timed out. If the worker subsequently attempts to record a heartbeat or return a
            result, it will be ignored.
             
            
Constraints:
 Declaration Syntax
 Declaration Syntax| C# | 
public string HeartbeatTimeout { get; set; }