How do I connect to the Electrs index? Goal:

My goal is to be able to have my own local blockchain indexed so I can perform searches based on public keys.

Blockchain:

wget https://bitcoincore.org/bin/bitcoin-core-0.19.1/bitcoin-0.19.1-x86_64-linux-gnu.tar.gz

I have a full node fully sync'ed



It seems electrs has now fully indexed the blockchain



Electrs was configued based on instructions here:

https://github.com/romanz/electrs/blob/master/doc/usage.md

What's next?

Unsure what to do next?  Do I need to create a C# app to connect to the Electrs index using JSON?  Do I need to use C# to connect to the rocksdb, which is the database used by electrs to index the blockchain?  If any of these is the next step, can someone please provide me with basic start code?  As in, how to connect my C# app to the index, pass it a parameter, in this case a public key, and retrieve a value back?
According to https://github.com/romanz/electrs

The server indexes the entire Bitcoin blockchain, and the resulting index enables fast queries for any given user wallet, allowing the user to keep real-time track of his balances and his transaction history using the Electrum wallet.
Supports Electrum protocol v1.4

It seems to me there are at least three ways forward:

Study the examples in the examples folder and add to electrs the facility you need using the interface of your choice.

Implement the Electrum protocol v1.4 in a custom client that you write. I would start by looking at the source code for Electrum.

use Electrum and import into it any address whose balance you are interested in.


The last seems like it might be the least work.