Setting stacktrace stringwriter initial buffer size to 256

instrumentation/src/main/java/io/opentelemetry/android/instrumentation/crash/CrashReporter.java

@@ -73,7 +73,7 @@ private void emitCrashEvent(Logger crashReporter, CrashDetails crashDetails) {
     }
 
     private String stackTraceToString(Throwable throwable) {
-        StringWriter sw = new StringWriter();
+        StringWriter sw = new StringWriter(256);
         PrintWriter pw = new PrintWriter(sw);
 
         throwable.printStackTrace(pw);