The ISimpleHttp object that is used to make HTTP requests.
The default value is a SimpleHttp instance.
Creates a new instance of HttpPyramid.
After the web request has succeeded, this method is called to determine if the response has delivered a valid tile image.
This default implementation just returns
After a web request has failed because of some reason other than
404 - Not Found, this method is called to determine if the response indicates a missing tile (no error reporting is necessary in this case).
This method is called for tile that has been requested.
The default implementation logs a warning messages for TileDataResult.Error. Subclasses may override this method in order to perform other logic, for example counting tile accesses to keep track of billing.