electrs is an efficient re-implementation of Electrum Server, inspired by
ElectrumX, Electrum Personal Server and bitcoincore-indexd.

The motivation behind this project is to enable a user to self host an Electrum
server, with required hardware resources not much beyond those of a full node.
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 balances and transaction history using the Electrum wallet.
Since it runs on the user's own machine, there is no need for the wallet to
communicate with external Electrum servers, thus preserving the privacy of the
user's addresses and balances.

Features:
* Supports Electrum protocol v1.4
* Maintains an index over transaction inputs and outputs
* Fast synchronization of the Bitcoin blockchain using HDD storage
* Low index storage overhead (~10%), relying on a local full node
* Efficient mempool tracker allowing better fee estimation
* Low CPU & memory usage (after initial indexing)
* txindex is not required for the Bitcoin node
* Uses a single RocksDB database, for better consistency and crash recovery