`workflow.Cause(ctx)` is not exposed

[raymondsze]

As title, the Cause(ctx) is in the internal package.

func Workflow(ctx workflow.Context, input string) (string, error) {
	ctx, cancel := workflow.WithCancelCause(ctx)
        cancel(errors.New("This workflow is canceled"))
        return "", ctx.Err()
}

This will get context cancelled error in client.GetWorkflowResult

To get the underling error correctly... it should be

func Workflow(ctx workflow.Context, input string) (string, error) {
	ctx, cancel := workflow.WithCancelCause(ctx)
        cancel(errors.New("This workflow is canceled"))
        return "", workflow.Cause(ctx.Err())
}

But workflow.Cause is not exposed in this library, so not possible to get the underlying error.

[cschleiden]

Implemented in: #483