Without dirtying a given file the metadata which contains the relaxant live restore entries will not be written out to the metadata file. This is mostly okay as eventually the live restore would complete and the metadata would no longer be relevant. However if we were to crash or frequently restart we'd never complete the live restore, redoing work over and over again.

To avoid this issue we should dirty the tree that we are live restoring every so often to ensure that checkpoint writes out the new bitmap to the metadata file.

Separately if the connection has begun closing, cease filling holes in a file.

Rework the fill holes path to support a dirty cadence.