Adding some additional info here. The quick way to create a new buffer is briefly mentioned at the end of the doc string:

b := new(bytes.Buffer)

or

b := &bytes.Buffer{}

TheBuffer struct define includes a 64 byte internalbootstrap field that is initially used for small allocations. Once the default size is exceeded, a byte sliceBuffer.buf is created and internally maintained.

As @leafbebop suggested we can pre-initalize thebuf field of theBuffer struct using a new slice.

b := bytes.NewBuffer(make([]byte,0,N))

I also found another option to use theGrow() method:

b := new(bytes.Buffer)b.Grow(n)

Also it's interesting to point out that the internalbuf slice will grow at a rate ofcap(buf)*2 + n. This means that if you've written 1MB into a buffer and then add 1 byte, yourcap() will increase to2097153 bytes.

Thebytes.buffer zero value is usable as is, so you can skip the initialization step. Code snippet fromdocs.

var b bytes.Buffer // A Buffer needs no initialization.b.Write([]byte("Hello "))

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