// by other code.
@SuppressWarnings("deprecation")
public static String readString(DataInputStream in) throws IOException {
DeprecatedUTF8 ustr = TL_DATA.get().U_STR;
ustr.readFields(in);
return ustr.toStringChecked();
}
static String readString_EmptyAsNull(DataInputStream in) throws IOException {
final String s = readString(in);
return s.isEmpty()? null: s;