refactor(persist): update file_store, sqlite, wallet to use bdk_chain::persist

Also update examples and remove bdk_persist crate.

example-crates/wallet_electrum/src/main.rs

@@ -3,6 +3,7 @@ const SEND_AMOUNT: Amount = Amount::from_sat(5000);
 const STOP_GAP: usize = 50;
 const BATCH_SIZE: usize = 5;
 
+use anyhow::anyhow;
 use std::io::Write;
 use std::str::FromStr;
 
@@ -11,24 +12,28 @@ use bdk_electrum::BdkElectrumClient;
 use bdk_file_store::Store;
 use bdk_wallet::bitcoin::{Address, Amount};
 use bdk_wallet::chain::collections::HashSet;
+use bdk_wallet::chain::persist::PersistBackend;
 use bdk_wallet::{bitcoin::Network, Wallet};
 use bdk_wallet::{KeychainKind, SignOptions};
 
 fn main() -> Result<(), anyhow::Error> {
     let db_path = std::env::temp_dir().join("bdk-electrum-example");
-    let db =
+    let mut db =
         Store::<bdk_wallet::wallet::ChangeSet>::open_or_create_new(DB_MAGIC.as_bytes(), db_path)?;
     let external_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/1'/0'/0/*)";
     let internal_descriptor = "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/1'/0'/1/*)";
-
+    let changeset = db
+        .load_changes()
+        .map_err(|e| anyhow!("load changes error: {}", e))?;
     let mut wallet = Wallet::new_or_load(
         external_descriptor,
         internal_descriptor,
-        db,
+        changeset,
         Network::Testnet,
     )?;
 
-    let address = wallet.next_unused_address(KeychainKind::External)?;
+    let address = wallet.next_unused_address(KeychainKind::External);
+    db.write_changes(&wallet.take_staged())?;
     println!("Generated Address: {}", address);
 
     let balance = wallet.balance();
@@ -67,7 +72,7 @@ fn main() -> Result<(), anyhow::Error> {
     println!();
 
     wallet.apply_update(update)?;
-    wallet.commit()?;
+    db.write_changes(&wallet.take_staged())?;
 
     let balance = wallet.balance();
     println!("Wallet balance after syncing: {} sats", balance.total());