Message length limitation affects parallel sending of transactions from different machines

Case 1:

Steps to Reproduce:
1. Run load test with following parameters on one of the clients:

python3 load_test.py --clients-list load_test_clients.list -t NYM -c 10 -r 100 --at-once

2. After completion of load test check InvalidMessageExceedingSizeException messages in logs.

ubuntu@californiaPerf1:/home/sovrin/.sovrin$ grep "InvalidMessageExceedingSizeException" /home/sovrin/.sovrin/Node1.log* | wc -l

Actual Results:
All 1000 transactions are written successfully, but there are 12 InvalidMessageExceedingSizeException messages appear in logs (there were no such exceptions before the test).

Expected Results:
If the massage from one client (running on one physical machine) exceeded limitation, transactions should not be written.

Case 2:

Steps to Reproduce:

1. Run load test with following parameters on one of the clients:

python3 load_test.py --clients-list load_test_clients.list -t NYM -c 5 -r 100 --at-once

=> All transactions are written, count of InvalidMessageExceedingSizeException messages was not increased.
2. After completion of previous script run load test with the same parameters at the same time on all clients.

Actual Results:
All transactions were written on 3 clients, but on the 4th client all of transactions were not written. Count of InvalidMessageExceedingSizeException in logs become equal to 60 (before test there were 48 messages).

Expected Results:
Transactions which were send by different clients should not affect each other.