Cause returns the underlying cause of the error, if possible.

Errorf formats according to a format specifier and returns the string as a value that satisfies error.

New returns an error with the supplied message.

WithMessage annotates err with a new message.

WithMessagef annotates err with the format specifier.

WithStack annotates err with a stack trace at the point WithStack was called.

Wrap returns an error annotating err with a stack trace at the point Wrap is called, and the supplied message.

Wrapf returns an error annotating err with a stack trace at the point Wrapf is called, and the format specifier.

Frame represents a program counter inside a stack frame.

StackTrace is stack of Frames from innermost (newest) to outermost (oldest).