A stroller is adapted to be connected with a car seat, and includes a frame, a footrest, and at least one locking device. The method includes changing, during transient operating states, the fuel staging of the at least one premix burner in accordance with combustion-induced pulsations which occur in the combustion chamber. The invitation request may be identified as directed to the second user and may include at least a device token associated with at least one of the first and second devices and an identification associated with at least one of the second device and the second user. The data pipe manager may be configured to maintain metadata identifying data blocks of the storage device that have been read by each data consumer, and to release backing storage corresponding to the data blocks that have been read by all data consumers. Third, apply a sliceslab separation magnetic field gradient so as to separate the at least two slicesslabs. The specific venturi geometries enable the printing of lines having sharp edges and particular widths, using relatively low pressures.