vlib/net: add buffered IO, x.net -> net (#6754)

vlib/os/os.v

@@ -860,7 +860,7 @@ pub fn home_dir() string {
 // write_file writes `text` data to a file in `path`.
 pub fn write_file(path string, text string) ? {
 	mut f := os.create(path)?
-	f.write(text)
+	f.write(text.bytes())
 	f.close()
 }