@Override
  public <T> T readBytes(final Function<Bytes, T> mapper) {
    final Bytes res = readBytes();
    try {
      return mapper.apply(res);
    } catch (final Exception e) {
      throw error(e, "Problem decoding bytes value");
    }
  }
Sets the input to the item provided (an offset to the beginning of an item) and check this is
valid.

@param item the value to which the current item is to be set.
ethereum/rlp/src/main/java/org/hyperledger/besu/ethereum/rlp/AbstractRLPInput.java