Returns the object only if it has been modified since the specified time, 
            otherwise returns a PreconditionFailed.
            
 Declaration Syntax
 Declaration Syntax| C# | 
[ObsoleteAttribute("The With methods are obsolete and will be removed in version 2 of the AWS SDK for .NET. See http://aws.amazon.com/sdkfornet/#version2 for more information.")] public GetObjectRequest WithUnmodifiedSinceDate( DateTime unmodifiedSinceDate )
 Parameters
 Parameters- unmodifiedSinceDate (DateTime)
- The date and time to test
 Return Value
 Return Valuethis instance
 Remarks
 Remarks
            When this is set the S3 object is returned only if it has not been modified since the specified time, otherwise
            return a 412 (precondition failed).