Update documentation

docs/src/main/asciidoc/telemetry-micrometer.adoc

@@ -603,7 +603,25 @@ The `@Timed` annotation will wrap the execution of a method and will emit the fo
 in addition to any tags defined on the annotation itself:
 class, method, and exception (either "none" or the simple class name of a detected exception).
 
-Using annotations is limited, as you can't dynamically assign meaningful tag values.
+Parameters to `@Counted` and `@Timed` can be annotated with `@MeterTag` to dynamically assign meaningful tag values.
+
+[source,java]
+----
+enum Currency { USD, EUR }
+
+// tags = type=with_enum, currency=${currency.toString()}
+@Timed(value="time_something", extraTags = {"type", "with_enum"})
+public Something calculateSomething(@MeterTag Currency currency) { ... }
+
+// tags = type=with_enum, the_currency=${currency.toString()}
+@Timed(value="time_something", extraTags = {"type", "with_enum"})
+public Something calculateSomething(@MeterTag(key="the_currency") Currency currency) { ... }
+---
+
+`MeterTag.expression` and `MeterTag.resolver` is currently not supported.
+
+IMPORTANT: Provided tag values MUST BE of LOW-CARDINALITY. If you fail to provide low-cardinality values, that can lead to performance issues of your metrics backend. Values should not come from the end-user since those could be high-cardinality.
+
 Also note that many methods, e.g. REST endpoint methods or Vert.x Routes, are counted and timed by the micrometer extension out of the box.
 
 == Support for the MicroProfile Metrics API