AWS SDK for .NET Documentation
ExecutionStartToCloseTimeout Property
AmazonAmazon.SimpleWorkflow.ModelStartChildWorkflowExecutionInitiatedEventAttributesExecutionStartToCloseTimeout Did this page help you?   Yes   No    Tell us about it...
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:

Length
0 - 8

Declaration Syntax
C#
public string ExecutionStartToCloseTimeout { get; set; }

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)