sclass JE_RepByte extends JEInstantCompressor {
  scaffolded public IJavaExpr compress(LByte data) {
    bool sc = scaffoldingEnabled(this);
    if (empty(data)) null;
    byte b = first(data);
    int n = l(data);
    for (int i = 1; i < n; i++)
      if ((byte) data.get(i) != b) {
        if (sc) scaffoldCalled(this, "diff at " + i + "/" + n);
        null;
      }
    ret functionCall repByte(n, b);
  }
}

Began life as a copy of #1033093