MULTI-THREADING BULK MESSAGES SEND

Multi-threading with v1.x was almost impossible to achieve.
In v2.x major structural changes were made in the node server API side in order to be able to achieve multi-threading send.
For people that don’t know what is multi-threading send, here is a simple illustration:
v1.x
Device1 -> send campaign -> to wait until finished -> Device2 -> send campaign -> to wait until finished -> Device3 -> send campaign -> finished.
v2.x
Device1 -> send campaign -> finished.
Device2 -> send campaign -> finished.
Device3 -> send campaign -> finished.
All sending is run in parallel