Unset the last error and return null if the event was never sent

src/Client.php

@@ -343,7 +343,11 @@ public function capture(array $payload)
             $payload
         );
 
-        $this->send($event);
+        if (false === $this->send($event)) {
+            $this->lastEvent = null;
+
+            return null;
+        }
 
         $this->lastEvent = $event;
 
@@ -356,15 +360,15 @@ public function capture(array $payload)
     public function send(Event $event)
     {
         if (!$this->config->shouldCapture($event)) {
-            return;
+            return false;
         }
 
         // should this event be sampled?
         if (mt_rand(1, 100) / 100.0 > $this->config->getSampleRate()) {
-            return;
+            return false;
         }
 
-        $this->transport->send($event);
+        return $this->transport->send($event);
     }
 
     /**

src/ClientInterface.php

@@ -109,7 +109,7 @@ public function captureLastError(array $payload = []);
      * Gets the last event that was captured by the client. However, it could
      * have been sent or still sit in the queue of pending events.
      *
-     * @return Event
+     * @return Event|null
      */
     public function getLastEvent();
 
@@ -127,14 +127,16 @@ public function getLastEventId();
      *
      * @param array $payload The data of the event being captured
      *
-     * @return string
+     * @return string|null
      */
     public function capture(array $payload);
 
     /**
      * Sends the given event to the Sentry server.
      *
      * @param Event $event The event to send
+     *
+     * @return bool|null
      */
     public function send(Event $event);