Bugfix in firmware partial sending

lib/session/MeasurementSession.h

@@ -52,6 +52,9 @@ public:
         assert(startIdx == lastIdx, "Not all data was sent");
     }
 
+    uint32_t getStartTime() const {
+        return currentChunk->getStartTime();
+    }
 private:
     void rotate() {
         if( otherChunkFilled() )

lib/session/StreamingMsgPackEncoder.h

@@ -200,12 +200,19 @@ public:
             sentBytes_ += sizeof(T) * length;
             return;
         } else {
-            const uint32_t elementsToSend = length - elementsToSkip;
+            sentBytes_ += sizeof(T) * elementsToSkip;
+            const uint32_t elementsRemaining = length - elementsToSkip;
+            const uint32_t maxElementsToSend = (maxBytes_ - sentBytes_) / sizeof(T);
+            const uint32_t elementsToSend = min(elementsRemaining, maxElementsToSend);
             if( elementsToSend == 0 ) {
                 sendingFinished_ = true;
                 return;
             } else {
                 encoder_.sendArrayPartialContents(data + elementsToSkip, elementsToSend);
+                sentBytes_ += sizeof(T) * elementsToSend;
+                if( elementsRemaining > elementsToSend ) {
+                    sendingFinished_ = true;
+                }
             }
         }
     }