Merge pull request #25 from singchia/fix/close-post-risk

avoid Cancel/Reset/Delay operation after Close

Merge pull request #22 from singchia/bench/resource

accelerate gc

Merge pull request #18 from singchia/feat/readme_optimize

feat: optimized readme

Merge pull request #15 from singchia/fix/batch_add_hang

fix: the cylically timer and Start immediately when calling NewTimer

Merge pull request #14 from singchia/feat/add_must_succeed

feat: An Add returns succeed after timer Close

Merge pull request #13 from singchia/feat/v2_directory

feat: adjuest directory

Merge pull request #13 from singchia/feat/v2_directory

feat: adjuest directory

feat: add close notification

fix: goroutine leak after Close

feat: renew scheduler