[Issue 444][fix] Use newError to build return error

[jonyhy96]

Fixes #444

Motivation

For better error assertion in client side.

Modifications

Fix newError and use newError to build return error in most case.

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): no
• The public API: no
• The schema: no
• The default values of configurations: no
• The wire protocol: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? GoDocs

[jonyhy96]

/cc @freeznet

[freeznet]

thanks for your work on this, LGTM.

[wolfstudy]

LGTM +1