Add support for RealmProxy#toString() to print length information for binary field

[joxon]

Fixes #1650

[cmelchior]

Hi @joxon Thank you very much for adding this 👏 . The change itself looks fine, but it would be nice with a unit test as well to ensure that the functionality both works now and doesn't break in the future.

Also, it looks you already signed our CLA 👍

[bmunkholm]

An update in the changelog.md would also be needed.

[joxon]

The change itself looks fine, but it would be nice with a unit test as well to ensure that the functionality both works now and doesn't break in the future.

Hi. I noticed there is an existing test case that could verify the correctness. Can I update that instead of writing new test case?

[bmunkholm]

@joxon Absolutely! That would be perfect!

[joxon]

Okay, the test cases are done. How should I update the changelog.md?

[cmelchior]

@joxon Thanks for doing this. I'll update the CHANGELOG you don't have to worry about it.

[Raynor999]

NPE：

 field is ByteArray -> {
                            emitStatement("stringBuilder.append(\"binary(\" + field.length + \")\")")
                        }

#6767

Caused by: java.lang.NullPointerException: Attempt to get length of null array