EMPTY_BYTE_ARRAY in client impl will cause compilation error

[XiaofeiCao]

• issue: https://dev.azure.com/azure-sdk/internal/_build/results?buildId=4217139&view=logs&j=42d88303-8e48-5332-e7e9-82bec1356e32&t=33740b31-17c1-53d0-4485-7f460d813a8f
• Currently, we'll generate EMPTY_BYTE_ARRAY as private static final member for a model, if it contains property that needs value expression conversion(null -> EMPTY_BYTE_ARRAY instead of new byte[0]).
  If we need similar transformation for client method parameters, this won't work since we won't generate this field member for clients.
  Possible solution is to track all client methods for optional ByteArray parameters. If any of them exists, generate EMPTY_BYTE_ARRAY as field member of client impl.
  Theoretically we need to track anywhere that needs default value expression conversion for ByteArray.

[weidongxu-microsoft]

Or just use new byte[0] in client?

I believe EMPTY_BYTE_ARRAY is mostly for performance?

[XiaofeiCao]

I believe EMPTY_BYTE_ARRAY is mostly for performance?

Yes.

Or just use new byte[0] in client?

Yeah we could. Though this would compromise some performance, and we need some hack to check for ByteArray when doing default value expression conversion.
We could first implement this, and see if we got any complaints.