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: circbuf.go
    path of file: ./repos/kubeedge/vendor/github.com/armon/circbuf
    
    the code of the file until where you have to start completion: package circbuf

import (
	"fmt"
)

// Buffer implements a circular buffer. It is a fixed size,
// and new writes overwrite older data, such that
    
func NewBuffer(size int64) (*Buffer, error) {
	if size <= 0 {
		return nil, fmt.Errorf("Size must be positive")
	}

	b := &Buffer{
		size: size,
		data: make([]byte, size),
	}
	return b, nil
}