Address review comments

Author: defanator

exporter.go

@@ -281,8 +281,9 @@ func registerCollector(logger *slog.Logger, transport *http.Transport,
 
 			// as we do not use any TLVs, header size should be pretty small, hence we only check for error, assuming the whole header went out in a single packet
 			_, err = header.WriteTo(conn)
-			if err != nil {
-				return nil, fmt.Errorf("writing proxyproto header: %w", err)
+			if err == nil {
+				conn.Close()
+				return nil, fmt.Errorf("writing proxyproto header via %s to %s: %w", network, addr, err)
 			}
 
 			return conn, nil