run test`ninja check-functional`
Test it locally on mainnet:
```
./src/bitcoind -chronik -chronikelectrumbind="127.0.0.1:50001:t"
```
```
echo '{"jsonrpc": "2.0", "method": "blockchain.block.headers", "params": [800000, 2016], "id": "test"}' | nc 127.0.0.1 50001
```