Function twz_rt_fd_pwrite

pub fn twz_rt_fd_pwrite(
    fd: RawFd,
    offset: Option<u64>,
    buf: &[u8],
    flags: IoFlags,
) -> Result<usize, IoError>

Write bytes from a buffer into a file descriptor, up to buf.len() bytes. On success, returns the number of bytes actually written, 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.