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: generic.go
    path of file: ./repos/corteza/extra/server-discovery/vendor/github.com/tidwall/btree
    
    the code of the file until where you have to start completion: // Copyright 2020 Joshua J Baker. All rights reserved.
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package btree

import "sync"

const (
	degree   = 128
	maxItems = degree*2 -
    
func (iter *GenericIter[T]) First() bool {
	if iter.tr == nil {
		return false
	}
	iter.atend = false
	iter.atstart = false
	iter.seeked = true
	iter.stack = iter.stack[:0]
	if iter.tr.root == nil {
		return false
	}
	n := iter.tr.root
	for {
		iter.stack = append(iter.stack, genericIterStackItem[T]{n, 0})
		if n.leaf() {
			break
		}
		n = (*n.children)[0]
	}
	s := &iter.stack[len(iter.stack)-1]
	iter.item = s.n.items[s.i]
	return true
}