Implement NamedRow changes for mysql

diesel/src/mysql/connection/stmt/iterator.rs

@@ -123,6 +123,7 @@ impl<'a> NamedStatementIterator<'a> {
             Ok(Some(())) => Some(Ok(NamedMysqlRow {
                 binds: &self.output_binds,
                 column_indices: self.metadata.column_indices(),
+                metadata: &self.metadata,
             })),
             Ok(None) => None,
             Err(e) => Some(Err(e)),
@@ -133,6 +134,7 @@ impl<'a> NamedStatementIterator<'a> {
 pub struct NamedMysqlRow<'a> {
     binds: &'a Binds,
     column_indices: &'a HashMap<&'a str, usize>,
+    metadata: &'a StatementMetadata,
 }
 
 impl<'a> NamedRow<Mysql> for NamedMysqlRow<'a> {
@@ -143,6 +145,14 @@ impl<'a> NamedRow<Mysql> for NamedMysqlRow<'a> {
     fn get_raw_value(&self, idx: usize) -> Option<MysqlValue<'_>> {
         self.binds.field_data(idx)
     }
+
+    fn field_names(&self) -> Vec<&str> {
+        self.metadata
+            .fields()
+            .iter()
+            .filter_map(|f| f.field_name())
+            .collect()
+    }
 }
 
 fn execute_statement(stmt: &mut Statement, binds: &mut Binds) -> QueryResult<()> {