support GetStateMultipleKeys GetPrivateDataMultipleKeys

[pfi79]

I have a desire to implement functionality so that GetStateMultipleKeys, GetPrivateDataMultipleKeys can be called from the chaincodes.

As it seems to me, the task is trivial and does not require creating a separate rfcs.

I will need to make changes to a few repositories: protos, chaincode and fabric.

1. peer will pass a flag if it supports these operations
2. if chaincode finds out that peer does not support these operations, it will send GetState in a loop. In other words, a new chaincode can be placed on any peer and nothing will break.

My only problem is that I won't be able to write code in java and node. I can read the code, but I can't write it. If someone will support this functionality for java and node, it will be great.

[pfi79]

@denyeart

[denyeart]

@pfi79 I agree the change is small enough that you could do it without an RFC. I think you can proceed with PRs. I believe the ledger APIs are already in place.

We typically lead with changes in fabric-chaincode-go, and then the other chaincode languages can catch up if people are interested. So my suggestion is to complete the fabric-chaincode-go changes, and then we can open issues in fabric-chaincode-node and fabric-chaincode-java to see if anybody wants to complete them (same holds true for the recent write batching).