The maximum duration for the child workflow execution. If the workflow execution is not closed within this duration, it will be timed out
            and force terminated. The valid values are integers greater than or equal to 0. An integer value can be used to specify the duration
            in seconds while NONE can be used to specify unlimited duration.
             
            
Constraints:
 Declaration Syntax
 Declaration Syntax| C# | 
public string ExecutionStartToCloseTimeout { get; set; }