in src/main/scala/middleware/FieldMetrics.scala [28:36]
override def beforeField(queryVal: FieldMetricState, mctx: MiddlewareQueryContext[Any, _, _], ctx: Context[Any, _]): BeforeFieldResult[Any, Unit] = continue
override def afterField(queryVal: FieldMetricState,
fieldVal: Unit, value: Any,
mctx: MiddlewareQueryContext[Any, _, _], ctx: Context[Any, _]): Option[Any] = {
val fieldName = ctx.parentType.name + "." + ctx.field.name
PrometheusMetrics.FieldUsageCount.labels(fieldName).inc()
None
}