code: async function createBlobReadStream(dir, oid) {
    const { object: content } = await git.readObject({ dir, oid });
    const stream = new PassThrough();
    stream.end(content);
    return stream;
  }
docs: Returns a stream for reading the specified blob.
  
  @param {string} dir git repo path
  @param {string} oid blob sha1
  @returns {Promise<Stream>} readable Stream instance