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: bytespipe.go
    path of file: ./repos/moby/pkg/ioutils
    
    the code of the file until where you have to start completion: package ioutils // import "github.com/docker/docker/pkg/ioutils"

import (
	"errors"
	"io"
	"sync"
)

// maxCap is the highest capacity to use in byte slices that buffer data.
const maxCap = 1e6

// minCap is the lowest capacity to use in byte slices that buffer data
const minCap = 64

// blockThreshold is the minimum number of bytes in the buffer which will cause
// a write to BytesPipe to block when allocating a new slice.
const blockThreshold = 1e6

var (
	// ErrClosed is returned when Write is called on a closed BytesPipe.
	ErrClosed = errors.New("write to closed BytesPipe")

	bufPools     = make(map[int]*sync.Pool)
	bufPoolsLock sync.Mutex
)


    
func (bp *BytesPipe) Read(p []byte) (n int, err error) {
	bp.mu.Lock()
	defer bp.mu.Unlock()
	if bp.bufLen == 0 {
		if bp.closeErr != nil {
			return 0, bp.closeErr
		}
		bp.readBlock = true
		bp.wait.Wait()
		bp.readBlock = false
		if bp.bufLen == 0 && bp.closeErr != nil {
			return 0, bp.closeErr
		}
	}

	for bp.bufLen > 0 {
		b := bp.buf[0]
		read, _ := b.Read(p) // ignore error since fixedBuffer doesn't really return an error
		n += read
		bp.bufLen -= read

		if b.Len() == 0 {
			// it's empty so return it to the pool and move to the next one
			returnBuffer(b)
			bp.buf[0] = nil
			bp.buf = bp.buf[1:]
		}

		if len(p) == read {
			break
		}

		p = p[read:]
	}

	bp.wait.Broadcast()
	return
}