test: add comprehensive tests and fix btree iterator concurrency (#339)

fix: improve concurrency safety and iterator behavior (#337)

Improvement/linter (#330)

fix typo error (#328)

Revert "update contributers"

update contributers

update changelog for v2.4.0

update iterator test

implement database iterator functionality (#326)

update comments

Add unit tests for AscendKeysRange and DescendKeysRange methods (#324)

Add AscendKeysRange and DescendKeysRange functions (#323)

use bytes.Equal instead of bytes.Compare

fix benchmark

update docs