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: headers.go
    path of file: ./repos/corteza/server/vendor/github.com/lestrrat-go/jwx/jwe
    
    the code of the file until where you have to start completion: package jwe

import (
	"context"

	"github.com/lestrrat-go/jwx/internal/base64"
	"github.com/lestrrat-go/jwx/internal/json"

	"github.com/lestrrat-go/iter/mapiter"
	"github.com/lestrrat-go/jwx/internal/iter"
	"github.com/pkg/errors"
)

type isZeroer interface {

    
func (h *stdHeaders) Iterate(ctx context.Context) Iterator {
	pairs := h.makePairs()
	ch := make(chan *HeaderPair, len(pairs))
	go func(ctx context.Context, ch chan *HeaderPair, pairs []*HeaderPair) {
		defer close(ch)
		for _, pair := range pairs {
			select {
			case <-ctx.Done():
				return
			case ch <- pair:
			}
		}
	}(ctx, ch, pairs)
	return mapiter.New(ch)
}