Add synchronized flag to subscriptions

[nguyer]

This PR adds a new flag to a subscription to indicate whether ETHConnect is still catching up or has caught up to the configured block height gap, and is keeping up with the chain head. When you do a GET on a subscription you will now see a synchronized field like this:

    {
        "created": "2023-07-24T17:02:29Z",
        "id": "sb-6e37fa9f-1a8c-48e1-6159-0f15701e15e5",
        "path": "/subscriptions/sb-6e37fa9f-1a8c-48e1-6159-0f15701e15e5",
        "name": "default_BatchPin_3078626437333333",
        "stream": "es-900f1d84-22fd-470f-54cd-b87d3e9e475a",
        "filter": {
            "address": [
                "0xbd7333f75351fe1bfc0e6f0bf2c01fc185beaf4a"
            ],
            "topics": [
                [
                    "0x805721bc246bccc732581be0c0aa2dd8f7ec93e97ba4b307be84428c98b0a12f"
                ]
            ]
        },
        "event": {
            "type": "event",
            "name": "BatchPin",
            "inputs": [
                {
                    "name": "author",
                    "type": "address",
                    "internalType": "address"
                },
                {
                    "name": "timestamp",
                    "type": "uint256",
                    "internalType": "uint256"
                },
                {
                    "name": "namespace",
                    "type": "string",
                    "internalType": "string"
                },
                {
                    "name": "uuids",
                    "type": "bytes32",
                    "internalType": "bytes32"
                },
                {
                    "name": "batchHash",
                    "type": "bytes32",
                    "internalType": "bytes32"
                },
                {
                    "name": "payloadRef",
                    "type": "string",
                    "internalType": "string"
                },
                {
                    "name": "contexts",
                    "type": "bytes32[]",
                    "internalType": "bytes32[]"
                }
            ],
            "outputs": null
        },
        "fromBlock": "latest",
        "synchronized": true
    }

[codecov-commenter]

Codecov Report

Merging #235 (c6d4152) into main (7791bec) will increase coverage by 0.00%.
The diff coverage is n/a.

❗ Current head c6d4152 differs from pull request most recent head e4bd748. Consider uploading reports for the commit e4bd748 to get more accurate results

@@           Coverage Diff           @@
##             main     #235   +/-   ##
=======================================
  Coverage   97.26%   97.26%           
=======================================
  Files          59       59           
  Lines        7521     7524    +3     
=======================================
+ Hits         7315     7318    +3     
- Misses        163      164    +1     
+ Partials       43       42    -1     

see 3 files with indirect coverage changes

[peterbroadhurst]

Really small (hopefully) request here @nguyer so that we don't return true until we've processed the logs between the end of the catchup window, and the head of the chain.

[peterbroadhurst]

I think we should wait to flick this to true until we've done our first eth_getFilterLogs and switch to eth_getFilterChanges:

firefly-ethconnect/internal/events/subscription.go

Lines 363 to 365 in e4bd748

	if s.filteredOnce {
	rpcMethod = "eth_getFilterChanges"
	}

[peterbroadhurst]

👍 - thanks for making that tweak. Looks great