sendAsync method doesn't follow SafeEventEmitter

[vanya2h]

I'm using json rpc middlewares with https://github.com/MetaMask/eth-json-rpc-middleware and it seems working with the most of injectable wallets. And recently I've discovered it doesn't work with Rainbow's so I dived deeper and discovered that your sendAsync method doesn't accept second argument - callback and instead returns just promise.

Example of problem:

window.rainbow.sendAsync(jsonRpcRequest, (err, jsonRpcResponse) => {
 // it'll never happen, callback is never called
})

[vanya2h]

Also I need to mention the format of response itself. Here's example of call to Ethereum Goerli

window.rainbow.sendAsync({
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_estimateGas",
    "params": [
        {
            "from": "0x76c5855e93bd498b6331652854c4549d34bc3a30",
            "data": "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",
            "to": "0x1723017329a804564bc8d215496c89eabf1f3211"
        }
    ]
})

I see two problems in the response:

1. The response doesn't follow standard json rpc response with such fields as jsonrpc, result, id and have just the raw value as it was sent via request API and not sendAsync
2. The response is not hexademical number and instead just a decimal number which is not working with some libraries that depends on estimateGas call
3. On some calls (e.g. eth_getBalance) returns unknown structure such as { "type": "BigNumber", "hex": "0x410ec70450f539bf" } and it seems very far away from the standards

[DanielSinclair]

@vanya2h Thanks for reporting this! This was fixed and released a few weeks back with additions to our window provider described here: rainbow-me/provider#9