public void setEndIfUnset(int end) {
      if (this.end == Integer.MAX_VALUE) {
        this.end = end;
      }
    }
Sets the end as given, but only if the instance is unclosed; otherwise, do nothing.

@param end {@code >= start;} the end
android/android_framework/dex-maker/src/main/java/com/android/dx/util/ByteArrayAnnotatedOutput.java