Gets the error response HTTP headers so that CloudFront specific information
             can be retrieved for debugging. Interesting fields are:
             a. x-amz-id-2
             b. x-amz-request-id
             c. Date
            
             A value can be retrieved from this HeaderCollection via:
             ResponseHeaders.Get("key");
             
 Declaration Syntax
 Declaration Syntax| C# | 
public WebHeaderCollection ResponseHeaders { get; }