/*
     * This function can be called for file handles that already have an in memory extent list. For
     * this to happen the destination file was created for the first time and a single file size
     * hole was initialized.
     *
     * There is a tricky scenario here:
     *   - Open a file that exists in the source, a.wt.
     *   - Create a new file in the destination to begin migrating the file to.
     *   - Crash.
     *   - Open the file a.wt again, we will see an a.wt in the destination and not create the
     *   necessary file length hole. We will also get an empty extent list string indicating a.wt is
     *   complete.
     */