How to compute the Sum512 of a stream of data without fixed known length about blake3

[lukechampine]

sure, here's how to do that in Go:

h := blake3.New(64, nil) // 512-bit output, no key
h.Write([]byte("This is the first array of byte."))
h.Write([]byte("<A VERY LONG STRING>"))
result := h.Sum(nil)

In Go, we typically use the io.Reader and io.Writer interfaces when working with lots of data. For example, if your data is stored in a file, you could do this:

f, _ := os.Open("path/to/file")
h := blake3.New(64, nil)
h.Write([]byte("This is the first array of byte."))
io.Copy(h, f) // stream the file contents into the hash
result := h.Sum(nil)

This works because io.Copy streams data from an io.Reader (in this case, f, the file) to an io.Writer (in this case, h, the hash).

Hope this helps!