Remove stale mem_info function

This used to be at least occasionally updated in aebdc2e,
in 7239fba it got removed

The user is required to call refresh themselves in order to not get stale
results after first access

lib/pitchfork/children.rb

@@ -17,11 +17,6 @@ def initialize
       @pending_molds = {} # Worker promoted to mold, not yet acknowledged
     end
 
-    def refresh
-      @workers.each_value(&:refresh)
-      @molds.each_value(&:refresh)
-    end
-
     def register(child)
       # Children always start as workers, never molds, so we know they have a `#nr`.
       @pending_workers[child.nr] = @workers[child.nr] = child
@@ -154,13 +149,5 @@ def fresh_workers
     def workers_count
       @workers.size
     end
-
-    def total_pss
-      total_pss = MemInfo.new(Process.pid).pss
-      @children.each do |_, worker|
-        total_pss += worker.meminfo.pss if worker.meminfo
-      end
-      total_pss
-    end
   end
 end

lib/pitchfork/worker.rb

@@ -32,14 +32,6 @@ def initialize(nr, pid: nil, generation: 0)
       end
     end
 
-    def meminfo
-      @meminfo ||= MemInfo.new(pid) if pid
-    end
-
-    def refresh
-      meminfo&.update
-    end
-
     def exiting?
       @exiting
     end