vendor: update buildkit to v0.18.0-rc1

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/go.opentelemetry.io/otel/sdk/metric/internal/aggregate/limit.go

@@ -0,0 +1,42 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package aggregate // import "go.opentelemetry.io/otel/sdk/metric/internal/aggregate"
+
+import "go.opentelemetry.io/otel/attribute"
+
+// overflowSet is the attribute set used to record a measurement when adding
+// another distinct attribute set to the aggregate would exceed the aggregate
+// limit.
+var overflowSet = attribute.NewSet(attribute.Bool("otel.metric.overflow", true))
+
+// limiter limits aggregate values.
+type limiter[V any] struct {
+	// aggLimit is the maximum number of metric streams that can be aggregated.
+	//
+	// Any metric stream with attributes distinct from any set already
+	// aggregated once the aggLimit will be meet will instead be aggregated
+	// into an "overflow" metric stream. That stream will only contain the
+	// "otel.metric.overflow"=true attribute.
+	aggLimit int
+}
+
+// newLimiter returns a new Limiter with the provided aggregation limit.
+func newLimiter[V any](aggregation int) limiter[V] {
+	return limiter[V]{aggLimit: aggregation}
+}
+
+// Attributes checks if adding a measurement for attrs will exceed the
+// aggregation cardinality limit for the existing measurements. If it will,
+// overflowSet is returned. Otherwise, if it will not exceed the limit, or the
+// limit is not set (limit <= 0), attr is returned.
+func (l limiter[V]) Attributes(attrs attribute.Set, measurements map[attribute.Distinct]V) attribute.Set {
+	if l.aggLimit > 0 {
+		_, exists := measurements[attrs.Equivalent()]
+		if !exists && len(measurements) >= l.aggLimit-1 {
+			return overflowSet
+		}
+	}
+
+	return attrs
+}