Moved classes from messaging package to sync package.

briar-api/src/org/briarproject/api/sync/TransportAck.java

@@ -0,0 +1,25 @@
+package org.briarproject.api.sync;
+
+import org.briarproject.api.TransportId;
+
+/** A packet acknowledging a {@link TransportUpdate}. */
+public class TransportAck {
+
+	private final TransportId id;
+	private final long version;
+
+	public TransportAck(TransportId id, long version) {
+		this.id = id;
+		this.version = version;
+	}
+
+	/** Returns the identifier of the updated transport. */
+	public TransportId getId() {
+		return id;
+	}
+
+	/** Returns the version number of the acknowledged update. */
+	public long getVersion() {
+		return version;
+	}
+}