add Pure performance

[zhilong-xu]

What this PR does / why we need it:

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

Release note:

[codecov[bot]]

Codecov Report

Merging #901 (78cc199) into master (61fedb2) will increase coverage by 0.03%. The diff coverage is 82.82%.

@@            Coverage Diff             @@
##           master     #901      +/-   ##
==========================================
+ Coverage   71.26%   71.30%   +0.03%     
==========================================
  Files         182      182              
  Lines       21326    21425      +99     
  Branches     3263     3277      +14     
==========================================
+ Hits        15199    15278      +79     
- Misses       5095     5109      +14     
- Partials     1032     1038       +6     

Impacted Files	Coverage Δ
delfin/drivers/pure/flasharray/pure_flasharray.py	83.94% <76.38%> (-1.61%)	:arrow_down:
delfin/drivers/pure/flasharray/consts.py	100.00% <100.00%> (ø)
delfin/drivers/pure/flasharray/rest_handler.py	40.24% <100.00%> (+1.49%)	:arrow_up:
delfin/drivers/fake_storage/__init__.py	93.63% <0.00%> (-0.77%)	:arrow_down: