add api for querying bundle status

[thegostep]

A commonly requested feature is for the relay to provide an api which allows searchers to query the status of their bundles.

Here is a sample api request:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "flashbots_getBundleStatus",
  "params": [bundleHash]
}

• bundleHash: String, the hex encoded bundle hash returned by the eth_callBundle and eth_sendBundle endpoints. This is calculated by taking the hash of the concatenated transaction hashes in the bundle:

function generateBundleHash(txs) {
  let hashes = '0x'
  for (let i = 0; i < txs.length; i++) {
    const tx = txs[i]

    hashes += tx.hash.slice(2)
  }

  return keccak256(hashes)
}

Example response:

{
  "is_high_reputation": true,
  "simulated_miner_payment": "128074959484158863",
  "simulated_gas_used": "470846",
  "simulation_timestamp": "1627383591"
}

[thegostep]

The response could potentially include more information about its status in the relay.

For example:

• simulation speed
• simulation error
• timestamp of submission to miners