Support real-time status

[YZahringer]

Real-time printer status support would be useful. A property and an event when changing status.

There are several statuses:

• https://reference.epson-biz.com/modules/ref_escpos/index.php?content_id=118
• https://reference.epson-biz.com/modules/ref_escpos/index.php?content_id=122

ESP-POS.NET Implementation:

• https://github.com/lukevp/ESC-POS-.NET/blob/master/ESCPOS_NET/Printers/PrinterStatus.cs
• https://github.com/lukevp/ESC-POS-.NET/blob/f33e8726abef76b99ed7da8c93946486e20468ac/ESCPOS_NET/Printers/BasePrinter.cs#L97

[montyclt]

Hi @YZahringer,

Supporting real-time changing event is in out roadmap, adding a event to IPrinter interface. We are to use the same strategy as @lukevp uses in his library, however, this project is paused (not abandoned) until 2020.

If you can, submit a PR implementing event in IPrinter interface and Printer class and we`ll merge as soon possible.