IGNITE-20481 Java client: Balance requests across connections

[weetyre]

Thank you for submitting the pull request to the Apache Ignite.

In order to streamline the review of the contribution we ask you to ensure the following steps have been taken:

JIRA ticket: https://issues.apache.org/jira/browse/IGNITE-20481

Description:

The ignite 2.15.0 version does not change the default channel for processing when the client is connected normally, resulting in load imbalance performance problems between ignite nodes. This modification adds a round-robin method to achieve the purpose of using a new available channel for each request to achieve complex balancing.

[weetyre]

@ptupitsyn @petrov-mg @ivan-fedorenkov @sk0x50 thanks in advance. :)

[weetyre]

@ptupitsyn @petrov-mg @ivan-fedorenkov @sk0x50 thanks in advance again. :)

[alex-plekhanov]

@weetyre, what problem are you trying to solve with this patch? When partition awareness is enabled connections are already balanced. Only reason to have partition awareness disabled is to have only one connection per client, so no balancing required here. Your patch breaks this behaviour (perhaps additionaly breaks other minor things).