Services: migrate to byte[] serialize() from ByteBuffer buffer()

core/src/main/java/org/bitcoinj/core/PeerAddress.java

@@ -189,7 +189,7 @@ public class PeerAddress extends Message {
                 throw new IllegalStateException();
             }
         } else {
-            stream.write(services.buffer().array());
+            stream.write(services.serialize());
             if (addr != null) {
                 // Java does not provide any utility to map an IPv4 address into IPv6 space, so we have to do it by
                 // hand.

core/src/main/java/org/bitcoinj/core/Services.java

@@ -136,15 +136,12 @@ public class Services {
     }
 
     /**
-     * Allocates a buffer and writes the node service bits into it. The buffer is backed by a byte array and it's
-     * already rewound for reading.
+     * Allocates a byte array and writes the node service bits into it.
      *
-     * @return buffer containing the service bits
+     * @return byte array containing the service bits
      */
-    public ByteBuffer buffer() {
-        ByteBuffer buf = write(ByteBuffer.allocate(BYTES));
-        ((Buffer) buf).rewind();
-        return buf;
+    public byte[] serialize() {
+        return write(ByteBuffer.allocate(BYTES)).array();
     }
 
     public String toString() {

core/src/main/java/org/bitcoinj/core/VersionMessage.java

@@ -171,7 +171,7 @@ public class VersionMessage extends Message {
     @Override
     public void bitcoinSerializeToStream(OutputStream buf) throws IOException {
         ByteUtils.writeInt32LE(clientVersion, buf);
-        buf.write(localServices.buffer().array());
+        buf.write(localServices.serialize());
         ByteUtils.writeInt64LE(time.getEpochSecond(), buf);
         receivingAddr.bitcoinSerializeToStream(buf);
         fromAddr.bitcoinSerializeToStream(buf);