In a time of year when availability is typically leveling off and turning downward, apartment availability in Boston is still on the rise in late April and surpassed the 8% level for the first time since the pandemic.   With the Mass. labor market sluggish and student enrollment leveling off at Boston-based schools, could we be looking at a downturn in the market?  The next 8 weeks will certainly be a stress test for demand as we see if the excess inventory is absorbed ahead of the 9/1 leasing date.