style: empty slice and redundant type conversion and .gitignore add develop tools

[demoManito]

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style

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• This PR title match the format: <type>(optional scope): <description>
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修改代码风格：

• 空切片申明方式 (https://github.com/golang/go/wiki/CodeReviewComments#declaring-empty-slices)
• 多余的类型转换
• ignore .vscode

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Which issue(s) this PR fixes:

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[codecov]

Codecov Report

Base: 66.18% // Head: 66.14% // Decreases project coverage by -0.04% ⚠️

Coverage data is based on head (21cf865) compared to base (9774687).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #348      +/-   ##
===========================================
- Coverage    66.18%   66.14%   -0.05%     
===========================================
  Files           85       85              
  Lines         8319     8320       +1     
===========================================
- Hits          5506     5503       -3     
- Misses        2454     2458       +4     
  Partials       359      359              

Impacted Files	Coverage Δ
pkg/route/tree.go	96.68% <100.00%> (+0.01%)	⬆️
pkg/common/timer/timer.go	61.90% <0.00%> (-19.05%)	⬇️

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