ObjectSpace.trace_object_allocations_debug_start

static VALUE
trace_object_allocations_debug_start(VALUE self)
{
    tmp_keep_remains = 1;
    if (object_allocations_reporter_registered == 0) {
        object_allocations_reporter_registered = 1;
        rb_bug_reporter_add(object_allocations_reporter, 0);
    }

    return trace_object_allocations_start(self);
}