ReloadActioninterface, and is executed right before the data reload from the source.
isbnservice is being reloaded, trigger asynchronous reload of
booksservice and proceed immediately:
isbnservice is being reloaded, trigger and wait synchronously for the reload of
booksservice. This way,
booksservice will always be reloaded strictly prior to
isbnservice is reloaded, reload in parallel
dvdsservices and wait for the positive result from both. In that case, reload