fix for outputs not working any more when receiving DDP or art-net pixels

This disables bus caching (and related speedups) while receiving realtime UDP pixels.

Its still totally unclear to me what happens, and why disabling the cache solves problems.

wled00/udp.cpp

@@ -153,11 +153,22 @@ void notify(byte callMode, bool followUp)
 void realtimeLock(uint32_t timeoutMs, byte md)
 {
   if (!realtimeMode && !realtimeOverride) {
+    // this code runs once when we enter realtime mode
+    // WLEDMM begin - we need to init segment caches before putting any pixels
+    if (strip.isServicing()) {
+      USER_PRINTLN(F("realtimeLock() enter RTM: strip is still drawing effects."));
+      strip.waitUntilIdle();
+    }
+    strip.service(); // WLEDMM make sure that all segments are properly initialized
+    busses.invalidateCache(true);
+    // WLEDMM end
+
     uint16_t stop, start;
     if (useMainSegmentOnly) {
       Segment& mainseg = strip.getMainSegment();
       start = mainseg.start;
       stop  = mainseg.stop;
+      mainseg.map1D2D = M12_Pixels; // WLEDMM no mapping
       mainseg.freeze = true;
     } else {
       start = 0;
@@ -199,6 +210,7 @@ void exitRealtime() {
   } else {
     strip.show(); // possible fix for #3589
   }
+  busses.invalidateCache(false);  // WLEDMM
   updateInterfaces(CALL_MODE_WS_SEND);
 }