add ping and example

solar_client/examples/ping.rs

@@ -0,0 +1,15 @@
+use anyhow::Result;
+use solar_client::{Client, SolarClient};
+
+const SERVER_ADDR: &str = "http://127.0.0.1:3030";
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    let client = Client::new(SERVER_ADDR.to_owned())?;
+
+    let ping = client.ping().await?;
+    println!("{}", ping);
+    // pong!
+
+    Ok(())
+}

solar_client/src/lib.rs

@@ -2,6 +2,8 @@ use anyhow::Result;
 
 #[jsonrpc_client::api]
 pub trait SolarClient {
+    async fn ping(&self) -> String;
+
     async fn whoami(&self) -> String;
 }