Remove unnecessary DumpOutput custom type

Hat tip @crazytonyli

#93 (comment)

Author: mokagio

Sources/Track.swift

@@ -84,15 +84,7 @@ class Track {
 
 /// 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()
+    var eventDump = ""
     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)
-    }
+    os_log("Sending an event from Track:\n%@", log: log, type: type, eventDump)
 }