before this, every time writting the index chunk data into the disk,
there are 4 I/O operations:
- open the file
- seek to the offset
- write the data
- close the file
this optimized this to open only once and continiously write all data.
This also makes it concurrent to load the files from object storage
Signed-off-by: yah01 <yang.cen@zilliz.com>
a27c0e86fd