InvalidOperationException thrown from Cancel

[bgrainger]

System.InvalidOperationException: Expected state to be (Querying|CancelingQuery) but was Failed.
   at MySql.Data.Serialization.MySqlSession.VerifyState(State state1, State state2)
   at MySql.Data.Serialization.MySqlSession.TryStartCancel(MySqlCommand command)
   at MySql.Data.MySqlClient.MySqlConnection.Cancel(MySqlCommand command)
   at Dapper.SqlMapper.GridReader.Dispose()
   at [Class].<MethodAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---

It's possible that the command is timing out (and killing the connection). If so, Cancel should be a no-op.

[bgrainger]

Couldn't create a test to reproduce it, but fixed the logic error that allowed this to happen.

[bgrainger]

Fixed in 0.31.0.