default int readUnsignedShort() {
    return readShort() & 0xFFFF;
  }
Reads the next item of this input (which must be exactly 2-bytes) as an unsigned short.

@return The value of the next item interpreted as an unsigned short.
@throws RLPException if the next item to read is a list, the input is at the end of its current
    list (and {@link #leaveList()} hasn't been called) or if the next item is not 2-bytes.
ethereum/rlp/src/main/java/org/hyperledger/besu/ethereum/rlp/RLPInput.java