pwritev

Writes the contents of bytes-like objects to a file descriptor at a given offset.

Combines the functionality of writev() and pwrite(). All buffers must be
a sequence of bytes-like objects.  Buffers are processed in array order.
Entire contents of first buffer is written before proceeding to second,
and so on. The operating system may set a limit (sysconf() value
SC_IOV_MAX) on the number of buffers that can be used.
This function writes the contents of each object to the file descriptor
and returns the total number of bytes written.

The flags argument contains a bitwise OR of zero or more of the
following flags:

- RWF_DSYNC
- RWF_SYNC
- RWF_APPEND
- RWF_DONTCACHE
- RWF_ATOMIC

Using non-zero flags requires Linux 4.7 or newer.