Update ReadMe with note on Go error vs C# enum

README.md

@@ -27,6 +27,8 @@ One difference in the Go version is that the `Store` shared a mutex between the
 
 I chose to keep the strong `DeviceId` in Go, even though it may be more idiomatic to keep it as a string, but I chose to lean more toward correctness, as a strong type allows better formatting, validation, etc. For this project, is it necessary? Not really, but it does make things a bit clearer, I think. 
 
+One other note is that in C#, when I add a device uptime history, I return an Enum of Added | OutOfSequence. In Go, I return an `errors.New("heartbeat out of sequence")` and check on that since there aren't a lot of error types. This isn't an enum, discriminated union, or something with exhaustive checking, however.
+
 ### Things to consider
 **Security** - never heard of it! Nothing is authenticated, but I'd expect a device to have a signature that is set up before hand.