Copyright 2018, OpenCensus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

package metricdata
LabelKey represents key of a label. It has optional description attribute.
type LabelKey struct {
	Key         string
	Description string
}
LabelValue represents the value of a label. The zero value represents a missing label value, which may be treated differently to an empty string value by some back ends.
type LabelValue struct {
	Value   string // string value of the label
	Present bool   // flag that indicated whether a value is present or not
}
NewLabelValue creates a new non-nil LabelValue that represents the given string.
func ( string) LabelValue {
	return LabelValue{Value: , Present: true}