Cause returns the root cause of this error.

GetSeverity returns the actual severity of the error, including inner errors.

New returns a new error object with message formed from given arguments.

PrintDeprecatedFeatureWarning prints a warning for deprecated and going to be removed feature.

PrintMigrateFeatureInfo prints a notice of the upcoming feature migration.

PrintRemovedFeatureError prints an error message for removed feature then return an error.

Error is an error object with underlying error.