Encapsulated the iteration of connections and msgs

Use of foldl for iteration is not hidden as implementation
detail.  Also hid details of how to message conn to set
tracing within API.

src/ibrowse_http_client.erl

@@ -19,6 +19,7 @@
          start/1,
          start/2,
          stop/1,
+         trace/2,
          send_req/7
         ]).
 
@@ -101,6 +102,9 @@ stop(Conn_pid) ->
             ok
     end.
 
+trace(Conn_pid, Bool) ->
+    catch Conn_pid ! {trace, Bool}.
+
 send_req(Conn_Pid, Url, Headers, Method, Body, Options, Timeout) ->
     gen_server:call(
       Conn_Pid,

src/ibrowse_lb.erl

@@ -122,10 +122,7 @@ handle_call(stop, _From, #state{ets_tid = undefined} = State) ->
     gen_server:reply(_From, ok),
     {stop, normal, State};
 handle_call(stop, _From, #state{ets_tid = Tid} = State) ->
-    ets:foldl(fun({Pid, _}, Acc) ->
-                  ibrowse_http_client:stop(Pid),
-                  Acc
-              end, [], Tid),
+    for_each_connection_pid(Tid, fun(Pid) -> ibrowse_http_client:stop(Pid) end),
     gen_server:reply(_From, ok),
     {stop, normal, State};
 
@@ -172,10 +169,7 @@ handle_info({trace, Bool}, #state{ets_tid = undefined} = State) ->
     put(my_trace_flag, Bool),
     {noreply, State};
 handle_info({trace, Bool}, #state{ets_tid = Tid} = State) ->
-    ets:foldl(fun({Pid, _}, Acc) when is_pid(Pid) ->
-		            catch Pid ! {trace, Bool},
-		            Acc
-	             end, undefined, Tid),
+    for_each_connection_pid(Tid, fun(Pid) -> ibrowse_http_client:trace(Pid, Bool) end),
     put(my_trace_flag, Bool),
     {noreply, State};
 
@@ -250,3 +244,7 @@ record_new_connection(Tid, Pid) ->
 
 record_request_for_connection(Tid, Pid) ->
     catch ets:update_counter(Tid, Pid, {2, 1, ?PIPELINE_MAX, ?PIPELINE_MAX}).
+
+for_each_connection_pid(Tid, Fun) ->
+    catch ets:foldl(fun({Pid, _}, _) -> Fun(Pid) end, undefined, Tid),
+    ok.