Add new type (#250)

- Add NETWORK_CORRUPTION type
- No longer need to flush_rx() if available is stuck in a loop, just return NETWORK_OVERRUN

Author: TMRh20

RF24Network.cpp

@@ -129,7 +129,6 @@ uint8_t RF24Network::update(void)
 
     while (radio.available()) {
         if (millis() > timeout) {
-            radio.flush_rx();
             return NETWORK_OVERRUN;
         }
 #if defined(ENABLE_DYNAMIC_PAYLOADS) && !defined(XMEGA_D3)
@@ -138,6 +137,10 @@ uint8_t RF24Network::update(void)
         frame_size = MAX_FRAME_SIZE;
 #endif
 
+        if (!frame_size) {
+            return NETWORK_CORRUPTION;
+        }
+
         // Fetch the payload, and see if this was the last one.
         radio.read(frame_buffer, frame_size);
 

RF24Network.h

@@ -123,10 +123,15 @@
 //#define NETWORK_ACK_REQUEST 192
 
 /**
- * Messages of this type indicate the network is being overrun with data & the RX FIFO has been flushed.
+ * Messages of this type indicate the network is being overrun with data.
  **/
 #define NETWORK_OVERRUN 160
 
+/**
+ * Messages of this type indicate radio data corruption & the RX FIFO has been flushed.
+ **/
+#define NETWORK_CORRUPTION 161
+
 /**
  * Messages of this type signal the sender that a network-wide transmission has been completed.
  *