Add some basic proto classes.

apm-network/src/main/proto/Downstream.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.skywalking.apm.network.collecor.proto";
+
+// nothing down stream from collector yet.
+message Downstream {
+}

apm-network/src/main/proto/TraceSegment.proto

@@ -3,15 +3,13 @@ syntax = "proto3";
 option java_multiple_files = true;
 option java_package = "org.skywalking.apm.network.trace.proto";
 
+import "Downstream.proto";
+
 service TraceSegmentService {
-    rpc collect (TraceSegmentObject) returns (CollectResult) {
+    rpc collect (TraceSegmentObject) returns (Downstream) {
     }
 }
 
 message TraceSegmentObject {
     string traceId = 1;
 }
-
-message CollectResult {
-    bytes resultCode = 1;
-}

apm-sniffer/apm-agent-core/pom.xml

@@ -35,6 +35,11 @@
             <artifactId>apm-logging-api</artifactId>
             <version>${project.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.skywalking</groupId>
+            <artifactId>apm-network</artifactId>
+            <version>${project.version}</version>
+        </dependency>
         <dependency>
             <groupId>net.bytebuddy</groupId>
             <artifactId>byte-buddy</artifactId>