public static PacketHeader Write(MySqlStreamWriter writer, string sql)
 {
     //for those who don't want to alloc an new packet
     //just write it into a stream
     writer.ReserveHeader();
     writer.WriteByte((byte)Command.STMT_PREPARE);
     writer.WriteString(sql);
     var h = new PacketHeader(writer.OnlyPacketContentLength, writer.IncrementPacketNumber());
     writer.WriteHeader(h);
     return h;
 }