private long positiveLong() {
    final long l = random.nextLong();
    return l < 0 ? Math.abs(l + 1) : l;
  }
Creates a UInt256 with a value that fits within maxByteSize

@param maxByteSize The byte size to cap this value to
@return the maximum size
ethereum/core/src/test-support/java/org/hyperledger/besu/ethereum/core/BlockDataGenerator.java