public Request deleteIndexAsync(final @NonNull String indexName, CompletionHandler completionHandler) {
        return deleteIndexAsync(indexName, /* requestOptions: */ null, completionHandler);
    }
public Request deleteIndexAsync(final @NonNull String indexName, CompletionHandler completionHandler) {
        return deleteIndexAsync(indexName,  null, completionHandler);
    }
public Request deleteIndexAsync ( final @ NonNull String indexName , CompletionHandler completionHandler ) { return deleteIndexAsync ( indexName , /* requestOptions: */ null , completionHandler ) ; }
Delete an index.

@param indexName         Name of index to delete.
@param completionHandler The listener that will be notified of the request's outcome.
@return A cancellable request.
Delete an index .