Always raise an error, as this method is not supported
without loading the additional NetClients package.
openOn: aURI ifFail: aBlock
Always evaluate aBlock and answer the result if the additional NetClients
package is not loaded. If it is, instead, return a WebEntity with the
contents of the resource specified by anURI, and only evaluate the block
if loading the resource fails.
openStreamOn: aURI
Check if aURI can be fetched from the Internet or from the local system,
and if so return a Stream with its contents. If this is not possible,
raise an exception.
openStreamOn: aURI ifFail: aBlock
Check if aURI can be fetched from the Internet or from the local system,
and if so return a Stream with its contents. If this is not possible,
instead, evaluate the zero-argument block aBlock and answer the result
of the evaluation.