Constant FOPEN_DIRECT_IO 

pub const FOPEN_DIRECT_IO: u32 = 1; // 1u32

Flags returned by the OPEN request

FOPEN_DIRECT_IO: bypass page cache for this open file FOPEN_KEEP_CACHE: don’t invalidate the data cache on open FOPEN_NONSEEKABLE: the file is not seekable FOPEN_CACHE_DIR: allow caching this directory FOPEN_STREAM: the file is stream-like (no file position at all) FOPEN_NOFLUSH: don’t flush data cache on close (unless FUSE_WRITEBACK_CACHE) FOPEN_PARALLEL_DIRECT_WRITES: Allow concurrent direct writes on the same inode FOPEN_PASSTHROUGH: passthrough read/write operations for this open file