Make sure "sending event" log msg and event dump are in the same line

This way, we avoid other `os_log` calls getting in between `os_log` and
`dump` and breaking the association between the two which makes the logs
harder to understand.

Author: mokagio

Sources/Track.swift

@@ -22,8 +22,7 @@ class Track {
         parselyTracker.startFlushTimer();
 
         pixel.beacon(event: event)
-        os_log("Sending an event from Track", log: OSLog.tracker, type:.debug)
-        dump(event.toDict())
+        os_log_sending_event(event)
     }
 
     func pageview(url: String, urlref: String = "", metadata: ParselyMetadata?, extra_data: Dictionary<String, Any>?, idsite: String) {
@@ -82,3 +81,18 @@ class Track {
         videoManager.sendHeartbeats()
     }
 }
+
+/// Utitlity to log sending event with a dump of the event.
+private func os_log_sending_event(_ event: Event, log: OSLog = .tracker, type: OSLogType = .debug) {
+    var eventDump = DumpOutput()
+    dump(event.toDict(), to: &eventDump)
+    os_log("Sending an event from Track:\n%@", log: log, type: type, eventDump.content)
+}
+
+private struct DumpOutput: TextOutputStream {
+    private(set) var content = ""
+
+    mutating func write(_ string: String) {
+        content.append(string)
+    }
+}