throttling 1.0.0

Contain "throttling" and "debouncing" async helper classes with listeners

[1.0.0] - 2021.03.08

• Refactoring
• Migrate to null safety
• Add effective dart
• Add badges
• Throttling and Debouncing extends Stream

[0.9.1] - 2021.02.06

• resolve pedantic issues
• add function documentation for throttle and debounce

[0.9.0] - 2020.11.05

• resolve a bug that can throw "Bad state: Cannot add new events after calling close"
• remove flutter dependency

[0.8.0] - 2019.06.11

• mod README.md

[0.6.0] - 2019.06.11

• format
• example

[0.5.0] - 2019.06.11

• initial release.