Allow InputStreamFactory.createInputStream() to throw IOException

[mvysny]

Describe your motivation

InputStreamFactory.createInputStream() creates an input stream. Since both reading and creating an input stream may throw IOException, it would be good to add the "throws IOException" clause to the createInputStream() function. For example:

        VaadinSession.getCurrent().getResourceRegistry().registerResource(new StreamResource("demo.pdf", () -> new FileInputStream("/home/mavi/Downloads/demo.pdf")));

This code doesn't compile because new FileInputStream() may throw a FileNotFoundException.

Describe the solution you'd like

Change the createInputStream() declaration to InputStream createInputStream() throws IOException.

Describe alternatives you've considered

-

[Legioth]

Adding an exception would be a breaking change in the hypothetical case that code in some application or 3rd party add-on would directly call that method rather than only using it to create a regular StreamResource instance.