Added destroy method to free up the memory buffers

[vadlakondaswetha]

Description

Added destroy method which will clean up the memory buffers when bwh is unInitialized.

Link to the issue in case of a bug fix.

NA

Testing details

1. Manual - NA
2. Unit tests - NA
3. Integration tests - NA

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 7 lines in your changes missing coverage. Please review.

Project coverage is 76.04%. Comparing base (3946230) to head (5a365d6).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
internal/bufferedwrites/buffered_write_handler.go	60.00%	3 Missing and 1 partial ⚠️
internal/fs/inode/file.go	40.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2839      +/-   ##
==========================================
- Coverage   76.05%   76.04%   -0.01%     
==========================================
  Files         118      118              
  Lines       16456    16490      +34     
==========================================
+ Hits        12515    12540      +25     
- Misses       3412     3419       +7     
- Partials      529      531       +2     

Flag	Coverage Δ
unittests	76.04% <83.33%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ashmeenkaur]

Minor comments