fs.readv(fd, buffers[, position], callback)


    fd 指定的文件中读取并使用 readv() 写入 ArrayBufferView 数组。

    Read from a file specified by fd and write to an array of ArrayBufferViews using readv().

    position is the offset from the beginning of the file from where data should be read. If typeof position !== 'number', the data will be read from the current position.

    The callback will be given three arguments: err, bytesRead, and buffers. bytesRead is how many bytes were read from the file.

    If this method is invoked as its util.promisify()ed version, it returns a promise for an Object with bytesRead and buffers properties.