public void setAccumulator(final PathBasedWorldStateUpdateAccumulator<?> accumulator) {
    this.accumulator = accumulator;
  }
Having a protected method to override the accumulator solves the chicken-egg problem of needing
a worldstate reference (this) when constructing the Accumulator.

@param accumulator accumulator to use.
ethereum/core/src/main/java/org/hyperledger/besu/ethereum/trie/pathbased/common/worldview/PathBasedWorldState.java