metrics: define more types
#define FLB_METRIC_N_RECORDS 0
#define FLB_METRIC_N_BYTES 1
+#define FLB_METRIC_OUT_OK_RECORDS 10
+#define FLB_METRIC_OUT_OK_BYTES 11
+#define FLB_METRIC_OUT_ERROR 12
+#define FLB_METRIC_OUT_RETRY 13
+
struct flb_metric {
int id;
int title_len;
