Add Example

README.md

@@ -14,6 +14,26 @@ go install github.com/jjti/go-spancheck/cmd/spancheck@latest
 spancheck ./...
 ```
 
+## Example
+
+```go
+func _() error {
+    // span.End is not called on all paths, possible memory leak
+    // span.SetStatus is not called on all paths
+    // span.RecordError is not called on all paths
+    _, span := otel.Tracer("foo").Start(context.Background(), "bar")
+
+    if true {
+        // return can be reached without calling span.End
+        // return can be reached without calling span.SetStatus
+        // return can be reached without calling span.RecordError
+        return errors.New("err")
+    }
+
+    return nil // return can be reached without calling span.End
+}
+```
+
 ## Configuration
 
 Only the `span.End()` check is enabled by default. The others can be enabled with `-enable-all`, `-enable-record-error-check`, or `-enable-set-status-check`.