/**
 * Copyright 2019, 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.
 */
/** TagKey represents a tag key */
export interface TagKey {
    /** The name of the key. */
    readonly name: string;
}
/** TagValue represents a tag value */
export interface TagValue {
    /** The value of a tag. */
    readonly value: string;
}
/** TagValueWithMetadata holds a TagValue and a TagMetadata. */
export interface TagValueWithMetadata {
    /** The tag value */
    readonly tagValue: TagValue;
    /** The metadata for the tag */
    readonly tagMetadata: TagMetadata;
}
/**
 * TagMetadata contains properties associated with a Tag.
 * Anytime a sender serializes a tag, sends it over the wire and receiver
 * deserializes the tag then the tag is considered to have travelled one hop.
 * There could be one or more proxy(ies) between sender and receiver. Proxies
 * are treated as transparent entities and they do not create additional hops.
 */
export interface TagMetadata {
    /**
     * For now, only special values of TagTtl are supported. In future,
     * additional properties may be added to address specific situations.
     */
    readonly tagTtl: number;
}
/** TagTtl is an integer that represents number of hops a tag can propagate */
export declare enum TagTtl {
    /**
     * NO_PROPAGATION is considered to have local scope and is used within the
     * process it created.
     */
    NO_PROPAGATION = 0,
    /** UNLIMITED_PROPAGATION can propagate unlimited hops. */
    UNLIMITED_PROPAGATION = -1
}