chore: AsyncReader use BufReader

[KKould]

before:

after:

+--------------------------------------------+---------+-------------+---------+----------+
|                                            | tonbo   | tonbo_foyer | rocksdb | tonbo_s3 |
+=========================================================================================+
| random range reads                         | 39207ms | 40021ms     | 36722ms | 55979ms  |
|--------------------------------------------+---------+-------------+---------+----------|
| random range reads                         | 38396ms | 39808ms     | 36585ms | 49915ms  |
|--------------------------------------------+---------+-------------+---------+----------|
| random range projection reads              | 28537ms | 29377ms     | 37077ms | 37680ms  |
|--------------------------------------------+---------+-------------+---------+----------|
| random range projection reads              | 28810ms | 29306ms     | 37003ms | 35845ms  |
|--------------------------------------------+---------+-------------+---------+----------|
| random range projection reads (4 threads)  | 17385ms | 18707ms     | 37233ms | 21270ms  |
|--------------------------------------------+---------+-------------+---------+----------|
| random range projection reads (8 threads)  | 17452ms | 17400ms     | 37396ms | 18609ms  |
|--------------------------------------------+---------+-------------+---------+----------|
| random range projection reads (16 threads) | 16728ms | 16596ms     | 35706ms | 17610ms  |
|--------------------------------------------+---------+-------------+---------+----------|
| random range projection reads (32 threads) | 16800ms | 16631ms     | 35659ms | 17723ms  |
+--------------------------------------------+---------+-------------+---------+----------+

[KKould]

How to calculate the io cost of minio to evaluate the difference

[KKould]

before:

0.33G

after:

1.11G