Handling of failure during GattClient operations is missing

[pan-]

The current GattClient API does not provide any way to catch a failure during a GattClient procedure. The following procedure miss this feature:

• Primary service discovery
• Characteristic discovery
• read attribute value
• write attribute value

With the current implementation, if something fail during one of this procedure, the client will never now that the procedure has ended and will not be able to react to such failures.

[rgrover]

thanks for pointing out this gap in our APIs. We should allow registering callbacks to discover erorrs.

[ciarmcom]

ARM Internal Ref: IOTSFW-1376