MySqlException.Data is empty

[bgrainger]

The Exception.Data dictionary can be used to "provide additional user-defined information about the exception".

MySQL bug 27436 asked for the error number to be added, so that code that generically handles DbException can read it.

Npgsql adds most public members to the Data dictionary they create: https://github.com/npgsql/npgsql/blob/7b13abaa958375f8166815ab3ffda54c2d17a89a/src/Npgsql/PostgresException.cs#L315-L333

We should use the "Server Error Code" key that Connector/NET uses, and also add "SqlState".

Note that Dictionary<string, object> should not be used as the implementation: npgsql/npgsql#2071.

[bgrainger]

Fixed in 0.49.0.