move/rename method?

Would be nice if there was a standardised move or rename method. Most backends support that natively and those that don't support it through a bit more of manual work (e.g. on s3, one has to copy the file and then delete the original). I've been monkey patching fs-store and s3-store to do this :/:

const stores = {
  fs: () => {
    const fsPath = path.join(__dirname, '../.tmp');
    const store = fsblobs(fsPath);
    store.absolutePath = (relPath) => {
      return path.join(fsPath, relPath);
    };
    store.move = (oldKey, newKey, cb) => {
      const oldPath = store.absolutePath(oldKey);
      const newPath = store.absolutePath(newKey);
      return fs.rename(oldPath, newPath, cb);
    };
    return store;
  },
  s3: () => {
    const client = new aws.S3({
      accessKeyId: config.aws.key,
      secretAccessKey: config.aws.secret,
    });
    const bucket = config.aws.s3.bucket;
    const store = s3blobs({ client, bucket });
    store.move = (oldKey, newKey) => {
      const copySource = bucket + '/' + oldKey;
      const params = {
        'CopySource': copySource,
        'Bucket': bucket,
        'Key': newKey,
      };
      client.copyObject(params, (err, data) => {
          if (err) return cb(err);
          client.deleteObject({
            'Bucket': bucket,
            'Key': oldKey,
          }, (_err) => {
            if (_err) return cb(_err);
            cb();
          });
        });
      });
    };
    return store;
  },
};

Start by reading the repository's abstract interface and test suite, then compare the fs-store and s3-store move examples in the issue. Determine how a standard move or rename operation should be represented across backends, including the copy-and-delete case, and add coverage showing the operation is complete.