piboxMsg() wants response length followed by response but not all messages provide it
piboxMsg() will check if a message type/subtype pair requires a response. If it does then it will read the response length first (4 bytes) followed by that many bytes in the response.
The problem is that messages currently sending responses (eg, network interfaces) don't send the length first. They just send the data.
Need to fix this to be consistent - either with or without the length field for responses.
Note: there don't appear to be any places where this is a problem as of yet. But the consistency in the API needs to be fixed.