Add kraken_ticker CLI for local testing of the client

swap/src/bin/kraken_ticker.rs

@@ -0,0 +1,21 @@
+use anyhow::{Context, Result};
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    tracing::subscriber::set_global_default(
+        tracing_subscriber::fmt().with_env_filter("trace").finish(),
+    )?;
+
+    let mut ticker = swap::kraken::connect()
+        .await
+        .context("Failed to connect to kraken")?;
+
+    loop {
+        ticker.changed().await?;
+
+        match &*ticker.borrow() {
+            Ok(rate) => println!("Rate update: {}", rate),
+            Err(e) => println!("Error: {:#}", e),
+        }
+    }
+}