Acre - Add bulk requests to shiroclient-sdk-go

[sam-at-luther]

No description provided.

[sam-at-luther]

The shiroclient-gw supports a feature called "bulk requests" which can let a caller batch up multiple phylum calls into a single transaction, without having to change their phylum code. This is implemented at the JSON-RPC layer in shiroclient-gw. However, we never have exposed this feature to the shiroclient-sdk-go, so presently our customers can't use it. This may be helpful to Acre, who is presently making back to back calls on some endpoints that result in MVCC conflicts and long depTx waits.