message: Derive Debug for Format
  It's useful to be able to inspect Format values when debugging.
diff: @@ -844,6 +844,7 @@ pub trait ToSql: fmt::Debug {
  /// Supported Postgres message format types
  ///
  /// Using Text format in a message assumes a Postgres `SERVER_ENCODING` of `UTF8`
  +#[derive(Debug)]
  pub enum Format {
  /// Text format (UTF-8)
  Text,
  