You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: queue.go
    path of file: ./repos/etcd/client/v3/experimental/recipes
    
    the code of the file until where you have to start completion: // Copyright 2016 The etcd 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 recipe

import (
	"context"

	"go.etcd.io/etcd/api/v3/mvccpb"
	v3 "go.etcd.io/etcd/client/v3"
)

// Queue implements a
    
func (q *Queue) Dequeue() (string, error) {
	// TODO: fewer round trips by fetching more than one key
	resp, err := q.client.Get(q.ctx, q.keyPrefix, v3.WithFirstRev()...)
	if err != nil {
		return "", err
	}

	kv, err := claimFirstKey(q.client, resp.Kvs)
	if err != nil {
		return "", err
	} else if kv != nil {
		return string(kv.Value), nil
	} else if resp.More {
		// missed some items, retry to read in more
		return q.Dequeue()
	}

	// nothing yet; wait on elements
	ev, err := WaitPrefixEvents(
		q.client,
		q.keyPrefix,
		resp.Header.Revision,
		[]mvccpb.Event_EventType{mvccpb.PUT})
	if err != nil {
		return "", err
	}

	ok, err := deleteRevKey(q.client, string(ev.Kv.Key), ev.Kv.ModRevision)
	if err != nil {
		return "", err
	} else if !ok {
		return q.Dequeue()
	}
	return string(ev.Kv.Value), err
}