public RegisterSpecSet withOffset(int delta) {
    int len = specs.length;
    RegisterSpecSet result = new RegisterSpecSet(len + delta);

    for (int i = 0; i < len; i++) {
      RegisterSpec spec = specs[i];
      if (spec != null) {
        result.put(spec.withOffset(delta));
      }
    }

    result.size = size;

    if (isImmutable()) {
      result.setImmutable();
    }

    return result;
  }
Returns an instance that is identical to this one, except that all register numbers are offset
by the given amount. Mutability of the result is inherited from the original.

@param delta the amount to offset the register numbers by
@return {@code non-null;} an appropriately-constructed instance
android/android_framework/dex-maker/src/main/java/com/android/dx/rop/code/RegisterSpecSet.java