Checks if UploadPolicySignature property is set
            
 Declaration Syntax
 Declaration Syntax| C# | 
public bool IsSetUploadPolicySignature()
 Return Value
 Return Valuetrue if UploadPolicySignature property is set
 Declaration Syntax
 Declaration Syntax| C# | 
public bool IsSetUploadPolicySignature()
 Return Value
 Return Value