The VFS pipe plugin exposes a control file for creating pipes and a set of pipe
directories. Opening and reading the "/new" returns a relative path to a
directory. That directory represents a pipe and contains an "in" and "out" file
for writing and reading respectively to the pipe.

Reads and writes are non-blocking and will complete short operations without
error, with the exception of reads on an empty pipe, which return READ_QUEUED.
The read and write capacity of a pipe may be queried by stat'ing the size of
"out" and "in" files.

When all "in" and "out" handles on a pipe as well as the initial handle on "new"
are closed, the pipe is destroyed.
