feat: Milliseconds to breadcrumbs (#777)

* resolves #776

Author: bruno-garcia

sentry/src/main/java/io/sentry/marshaller/json/JsonMarshaller.java

@@ -295,8 +295,10 @@ private void writeBreadcumbs(JsonGenerator generator, List<Breadcrumb> breadcrum
         generator.writeArrayFieldStart("values");
         for (Breadcrumb breadcrumb : breadcrumbs) {
             generator.writeStartObject();
-            // getTime() returns ts in millis, but breadcrumbs expect seconds
-            generator.writeNumberField("timestamp", breadcrumb.getTimestamp().getTime() / 1000);
+            TimeZone tz = TimeZone.getTimeZone("UTC");
+            DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
+            df.setTimeZone(tz);
+            generator.writeStringField("timestamp", df.format(breadcrumb.getTimestamp()));
 
             if (breadcrumb.getType() != null) {
                 generator.writeStringField("type", breadcrumb.getType().getValue());

sentry/src/test/java/io/sentry/marshaller/json/JsonMarshallerTest.java

@@ -245,13 +245,13 @@ public void testEventBreadcrumbsWrittenProperly() throws Exception {
         final JsonOutputStreamParser jsonOutputStreamParser = newJsonOutputStream();
 
         Breadcrumb breadcrumb1 = new BreadcrumbBuilder()
-            .setTimestamp(new Date(1463169342000L))
+            .setTimestamp(new Date(1463169342123L))
             .setLevel(Breadcrumb.Level.INFO)
             .setCategory("foo")
             .setMessage("test1")
             .build();
         Breadcrumb breadcrumb2 = new BreadcrumbBuilder()
-            .setTimestamp(new Date(1463169343000L))
+            .setTimestamp(new Date(1463169343111L))
             .setLevel(Breadcrumb.Level.INFO)
             .setCategory("foo")
             .setMessage("test2")

sentry/src/test/resources/io/sentry/marshaller/json/jsonmarshallertest/testBreadcrumbs.json

@@ -17,13 +17,13 @@
   "breadcrumbs": {
     "values": [
       {
-        "timestamp": 1463169342,
+        "timestamp": "2016-05-13T19:55:42.123Z",
         "level": "info",
         "message": "test1",
         "category": "foo"
       },
       {
-        "timestamp": 1463169343,
+        "timestamp": "2016-05-13T19:55:43.111Z",
         "level": "info",
         "message": "test2",
         "category": "foo"