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

import (
	
)
FromContext returns the tag map stored in the context.
The returned tag map shouldn't be mutated.
	 := .Value(mapCtxKey)
	if  == nil {
		return nil
	}
	return .(*Map)
}
NewContext creates a new context with the given tag map. To propagate a tag map to downstream methods and downstream RPCs, add a tag map to the current context. NewContext will return a copy of the current context, and put the tag map into the returned one. If there is already a tag map in the current context, it will be replaced with m.
func ( context.Context,  *Map) context.Context {
	return context.WithValue(, mapCtxKey, )
}

type ctxKey struct{}