Copy copies provided err to the new one.

Get convert provided error to the custom and if it is not custom - return nil.

Is compare provided errors.

IsType try to convert provided error to custom and compare error types.

Join all provided errors into one error.

New creates new Error object with provided message.

TryGet convert provided error to the custom and say it is custom or not.

Type returns type of custom error.

Wrap convert provided error to custom with the provided error type and message.

Error is custom error which implements built-in error interface.