to_sql is very slow for sql server with sqlalchemy
df.to_sql is very slow, and takes hours, when connecting to sql server using sql alchemy connection
https://github.com/mkleehammer/pyodbc/wiki/Features-beyond-the-DB-API#fast_executemany

Performance is much faster after using fast_executemany

```
@event.listens_for(engine_local, 'before_cursor_execute')
def receive_before_cursor_execute(conn, cursor, statement, params, context, executemany):
    if executemany:
        cursor.fast_executemany = True
```

Can enable fast_executemany in to_sql implementation for SQL Server
