What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind performance

What does this PR do / why do we need it:

1. Interface change :_Constant to Constant
2. improve comment in class Initializer

Which issue(s) this PR fixes:

#I1D8P1: Interface change :`_Constant` to `Constant`
Fixes #

Special notes for your reviewers: