refactor: support Egg 2

[brickyang]

Checklist

• npm test passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

Description of change

[codecov-io]

Codecov Report

Merging #6 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master     #6   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           3      3           
  Lines          76     76           
=====================================
  Hits           76     76

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