withConnection<T> method
Get free connection from this pool (possibly new connection) and invoke callback function with this connection
After callback completes, connection is returned into pool as idle connection This function returns callback result
Implementation
FutureOr<T> withConnection<T>(
FutureOr<T> Function(MySQLConnection conn) callback) async {
final conn = await _getFreeConnection();
final result = await callback(conn);
_releaseConnection(conn);
return result;
}