public int getFileSize() {
    if (fileSize < 0) {
      throw new RuntimeException("file size not yet known");
    }

    return fileSize;
  }
Gets the total file size, if known.

<p>This is package-scope in order to allow the {@link HeaderSection} to set itself up properly.

@return {@code >= 0;} the total file size
@throws RuntimeException thrown if the file size is not yet known
android/android_framework/dex-maker/src/main/java/com/android/dx/dex/file/DexFile.java