[libbpmclient] Old received message on receive buffer

[lerwys]

This problem arises from the fact that, sometimes, we give up too soon from waiting the received message. Most of the time, the message is just a bit delayed, causing the client prematurely abort the operation.

However, due to the asynchronous nature of libbpmclient, the message will arrive (eventually) and be put in the receive buffer.

On the following operation, even if the message arrives on time, there will be an earlier message in the buffer which will be mistakenly detected as the message for the current operation.

A possibility to handle this would be to use a single client instance per thread and add more information to the reply packet. For instance we could have the operation number which this reply belongs to and a sequence number to avoid detecting an earlier (and handled) message.

[lerwys]

This issue is related to lnls-dig/bpm-epics-ioc#3, lnls-dig/bpm-epics-ioc#4, lnls-dig/bpm-epics-ioc#5