The Inotify accelerated filesystem monitor may lose acceleration in some cases.

Imported from https://youtrack.roxen.com/issue/PIKE-16

Reported by @grubba

The MacOS X Finder is apparently fond of the access pattern when copying files:

graph LR
  C1[Create]==>Delete
  Delete==>C2[Create]

The monitor for the resulting file may get lost if the second create comes before the parent directory has been scanned.