Allow using system instructions

examples/system_instruction.rs

@@ -0,0 +1,50 @@
+use std::sync::Arc;
+
+use gemini_rs::prelude::*;
+
+use gcp_auth::AuthenticationManager;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tracing_subscriber::fmt().init();
+    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 system_instruction = "Answer as if you were Winston Churchill";
+    let prompt = "What is the airspeed of an unladen swallow?";
+
+    let request = GenerateContentRequest {
+        contents: vec![Content {
+            role: "user".to_string(),
+            parts: Some(vec![Part::Text(prompt.to_string())]),
+        }],
+        system_instruction: Some(Content {
+            role: "system".to_string(),
+            parts: Some(vec![Part::Text(system_instruction.to_string())]),
+        }),
+        ..Default::default()
+    };
+
+    let result = gemini
+        .generate_content(&request, "gemini-1.0-pro-002")
+        .await?;
+
+    if let GenerateContentResponse::Ok {
+        candidates,
+        usage_metadata: _,
+    } = result
+    {
+        println!("Response: {:?}", candidates[0].get_text().unwrap());
+    }
+
+    Ok(())
+}