Adds a count_token methods to the Gemini Clent

examples/count-tokens.rs

@@ -0,0 +1,32 @@
+use std::sync::Arc;
+
+use gemini_rs::prelude::*;
+
+use gcp_auth::AuthenticationManager;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let authentication_manager = Arc::new(AuthenticationManager::new().await?);
+    let api_endpoint = std::env::var("API_ENDPOINT")?;
+    let project_id = std::env::var("PROJECT_ID")?;
+    let location_id = std::env::var("LOCATION_ID")?;
+
+    let gemini = GeminiClient::new(
+        authentication_manager,
+        api_endpoint,
+        project_id,
+        location_id,
+    );
+
+    let prompt = "What is the airspeed of an unladen swallow?";
+    let request = CountTokensRequest {
+        contents: Content {
+            role: "user".to_string(),
+            parts: Some(vec![Part::Text(prompt.to_string())]),
+        },
+    };
+    let result = gemini.count_tokens(&request, "gemini-pro").await?;
+    println!("Response: {:?}", result);
+
+    Ok(())
+}