As is a wrapper of built-in errors.As.

Cause returns the result of repeatedly calling the Unwrap method on err, if err's type implements an Unwrap method.

Is is a wrapper of built-in errors.Is.

New returns a new error with a stacktrace of recent call frames.

Newf is like New, but it formats input according to a format specifier.

Unwrap is a wrapper of built-in errors.Unwrap.

Wrap returns a new error, which wraps another error with a stacktrace containing recent call frames.

Wrapf is like Wrap but the message is formatted with the supplied format specifier.