bump up version to v2.5.1 - Make encoding JSON string value 2x faster - Add documents to all APIs with doc tests and revise readme
bump up version to v2.5.0
bump up version to v2.4.0
bump up version to v2.3.0
bump up to v2.2.0
bump up version to 2.1.1
bump up version to 2.1.0
bump up version to v2.0.3
bump up version to 2.0.2
bump up version to 2.0.1