fails:File#flock blocks if trying to lock an exclusively locked file
fails:File#flock returns 0 if trying to lock a non-exclusively locked file
fails:File#flock on Solaris or Java fails with EBADF acquiring exclusive lock on read-only File
fails:File#flock on Solaris or Java fails with EBADF acquiring shared lock on read-only File
slow:File#flock returns false if trying to lock an exclusively locked file
solaris:File#flock exclusively locks a file
solaris:File#flock non-exclusively locks a file
solaris:File#flock blocks if trying to lock an exclusively locked file
solaris:File#flock returns 0 if trying to lock a non-exclusively locked file
solaris:File#flock on Solaris fails with EBADF acquiring exclusive lock on read-only File
solaris:File#flock on Solaris fails with EBADF acquiring shared lock on read-only File
