- how to inform coda when size of a directory changes?
- test for server options
- conditinal PUT, if no locks are used
  apche2/mod-dav don't handle conditional PUT.
  Watch apache bugreport.
- delete files when cache size gets to big
- more elaborated write back strategy
- make debug a run time option?
- use fuse kernel module
- option to add additional headers on per server base

