CAR Reader for supporting carlet

[LucRoy]

*** Encloud Specific ***

1. encloud are using Anelace + Carlet for data prep and with this we generate CAR files and splits without a root cid

2. Currently on edge and delta the add-car endpoint is being developed and it will be designed to handle CAR files in the format as prepared by go-car, i.e., with a root cid

3. Additionally, we had a discussion around whether the response from edge for getting a CAR file should return the raw bytes or a CAR file. For our use case we want the raw bytes to be returned. For this I understand we need to write a special reader, that we discussed about potentially co developing.

[alvin-reyes]

@LucRoy

You can use the following:

// gocarv2 package
car, err := gocarv2.NewBlockReader(file)

// do for loop to read the blocks (don't read the roots)

buf := new(bytes.Buffer)
for {
    block, err := car.Next()
   _, err = io.Copy(buf, bytes.NewReader(    block.RawData()))
   // return the buf that has all the block raw data
}