Copyright 2017, 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 tag
Key represents a tag key.
type Key struct {
	name string
}
NewKey creates or retrieves a string key identified by name. Calling NewKey more than once with the same name returns the same key.
func ( string) (Key, error) {
	if !checkKeyName() {
		return Key{}, errInvalidKeyName
	}
	return Key{name: }, nil
}
MustNewKey returns a key with the given name, and panics if name is an invalid key name.
func ( string) Key {
	,  := NewKey()
	if  != nil {
		panic()
	}
	return 
}
Name returns the name of the key.
func ( Key) () string {
	return .name