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: iterator.go
    path of file: ./repos/plumber/vendor/github.com/go-redis/redis/v8
    
    the code of the file until where you have to start completion: package redis

import (
	"context"
	"sync"
)

// ScanIterator is used to incrementally iterate over a collection of elements.
// It's safe for concurren
    
func (it *ScanIterator) Next(ctx context.Context) bool {
	it.mu.Lock()
	defer it.mu.Unlock()

	// Instantly return on errors.
	if it.cmd.Err() != nil {
		return false
	}

	// Advance cursor, check if we are still within range.
	if it.pos < len(it.cmd.page) {
		it.pos++
		return true
	}

	for {
		// Return if there is no more data to fetch.
		if it.cmd.cursor == 0 {
			return false
		}

		// Fetch next page.
		switch it.cmd.args[0] {
		case "scan", "qscan":
			it.cmd.args[1] = it.cmd.cursor
		default:
			it.cmd.args[2] = it.cmd.cursor
		}

		err := it.cmd.process(ctx, it.cmd)
		if err != nil {
			return false
		}

		it.pos = 1

		// Redis can occasionally return empty page.
		if len(it.cmd.page) > 0 {
			return true
		}
	}
}