OpenBSD and ZFS on Solaris don't support direct I/O. On Windows the synchronous
ioengines don't support direct I/O. Default: false.
.TP
-.BI atomic \fR=\fPbool
-If value is true, attempt to use atomic direct I/O. Atomic writes are
-guaranteed to be stable once acknowledged by the operating system. Only
-Linux supports O_ATOMIC right now.
-.TP
.BI buffered \fR=\fPbool
If value is true, use buffered I/O. This is the opposite of the
\fBdirect\fR option. Defaults to true.