Don't use malloc in S2. Also don't overwrite S2Cell's v-table in S2's region covering algorithm
Missing include
Removed Candidate::num_children field
Isolated fix for #3111 out of michel_3111_next_batch. Code review 2152
Merge branch 'v1.15.x' into daniel_3201
Fix changefeed bug, add some debug-mode instrumentation to mailboxes.
Fixed capitalization.
Merge branch 'v1.15.x' into daniel_2988_coro_stack