It's often the case that you want to write a file or files to the disk
image.
-For small, single files, use L</guestfs_write_file>. This call
-currently contains a bug which limits the call to plain text files
-(not containing ASCII NUL characters).
+For small, single files, use L</guestfs_write>.
To upload a single file, use L</guestfs_upload>. This call has no
limits on file content or size (even files larger than 4 GB).