docs: update scanner development guide

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I1968c93cf2d6c8b4f250bd7f88cc45846a6a6964

docs/SCANNERS.md

@@ -28,21 +28,36 @@ pscand-core = { workspace = true }
 ## Implementing the `Scanner` trait
 
 ```rust
-use pscand_core::scanner::Scanner;
+use std::time::Duration;
+use pscand_core::scanner::{Scanner, ScannerCollectionResult, MetricValue, Result};
 use pscand_macros::scanner;
+use std::collections::HashMap;
 
 pub struct CustomScanner;
 
 impl Scanner for CustomScanner {
-    fn name(&self) -> &str {
+    fn name(&self) -> &'static str {
         "custom"
     }
 
-    fn collect(&self) -> Result<serde_json::Value, Box<dyn std::error::Error>> {
-        // Collect your metrics
-        Ok(serde_json::json!({
-            "value": 42
-        }))
+    fn interval(&self) -> Duration {
+        Duration::from_secs(5)
+    }
+
+    fn init(&mut self, _config: &toml::Value) -> Result<()> {
+        // Initialize your scanner (e.g., open hardware interfaces)
+        Ok(())
+    }
+
+    fn collect(&self) -> ScannerCollectionResult {
+        let mut metrics = HashMap::new();
+        metrics.insert("value".to_string(), MetricValue::from_i64(42));
+        Ok(metrics)
+    }
+
+    fn cleanup(&mut self) -> Result<()> {
+        // Clean up resources
+        Ok(())
     }
 }