How do you set errors that are non-field specific?

[matthew-dean]

The API has setFieldError and setErrors, the latter of which is also defined as being field-specific. But it's often the case that the backend may return a general error that is not specific to any field, BUT there's a need to have a single "point of truth" for all errors. Is there a simple way to combine "general" errors and form-specific errors?