Provide support for IOTracing for ReadAsync API (#9833)
Summary:
Same as title
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9833
Test Plan:
Add unit test and manually check the output of tracing logs
For fixed readahead_size it logs as:
```
Access Time : 193352113447923 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 15075 , IO Status: OK, Length: 12288, Offset: 659456
Access Time : 193352113465232 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 14425 , IO Status: OK, Length: 12288, Offset: 671744
Access Time : 193352113481539 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13062 , IO Status: OK, Length: 12288, Offset: 684032
Access Time : 193352113497692 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13649 , IO Status: OK, Length: 12288, Offset: 696320
Access Time : 193352113520043 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 19384 , IO Status: OK, Length: 12288, Offset: 708608
Access Time : 193352113538401 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 15406 , IO Status: OK, Length: 12288, Offset: 720896
Access Time : 193352113554855 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13670 , IO Status: OK, Length: 12288, Offset: 733184
Access Time : 193352113571624 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13855 , IO Status: OK, Length: 12288, Offset: 745472
Access Time : 193352113587924 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 13953 , IO Status: OK, Length: 12288, Offset: 757760
Access Time : 193352113603285 , File Name: 000026.sst , File Operation: Prefetch , Latency: 59 , IO Status: Not implemented: Prefetch not supported, Length: 8868, Offset: 898349
```
For implicit readahead:
```
Access Time : 193351865156587 , File Name: 000026.sst , File Operation: Prefetch , Latency: 48 , IO Status: Not implemented: Prefetch not supported, Length: 12266, Offset: 391174
Access Time : 193351865160354 , File Name: 000026.sst , File Operation: Prefetch , Latency: 51 , IO Status: Not implemented: Prefetch not supported, Length: 12266, Offset: 395248
Access Time : 193351865164253 , File Name: 000026.sst , File Operation: Prefetch , Latency: 49 , IO Status: Not implemented: Prefetch not supported, Length: 12266, Offset: 399322
Access Time : 193351865165461 , File Name: 000026.sst , File Operation: ReadAsync , Latency: 222871 , IO Status: OK, Length: 135168, Offset: 401408
```
Reviewed By: anand1976
Differential Revision: D35601634
Pulled By: akankshamahajan15
fbshipit-source-id: 5a4f32a850af878efa0767bd5706380152a1f26e
c8bae6e29c