Function twz_rt_fd_preadv

pub fn twz_rt_fd_preadv(
    fd: RawFd,
    offset: Option<u64>,
    ios: &[IoSlice],
    flags: IoFlags,
) -> Result<usize, IoError>

Read a file descriptor into a multiple buffers. On success, returns the number of bytes actually read, which may be fewer than requested. If offset is None, use the file descriptor’s internal position. If the file descriptor refers to a non-seekable file, and offset is Some, this function returns an error.