private static void writeSpaces(Writer out, int amt) throws IOException {
    while (amt > 0) {
      out.write(' ');
      amt--;
    }
  }
Writes the given number of spaces to the given writer.

@param out {@code non-null;} where to write
@param amt {@code >= 0;} the number of spaces to write
android/android_framework/dex-maker/src/main/java/com/android/dx/util/TwoColumnOutput.java