To isolate commands we use immutable data structure from immer library. Each mutation on a container produces a new version of it, one can read concurrently without any lock. See details Immer.

Use join_server binary to test with the input from tests/test_cmd.txt:

• bulk_server 9000, and then
• cat tests/test_cmd.txt | nc localhost 9000

you should get the following

OK
ERR duplicate 0
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
3,violation,proposal
4,quality,example
5,precision,lake
0,lean,
1,sweater,
2,frank,
6,,flour
7,,wonder
8,,selection
OK
OK