A series of snippets of streaming protobuf serialization code, works with protobuf 2.4.1 but not 2.5.0rc1.

gistfile1.java

// some initialization which takes place in the constructor of the streamed
// protobug message writer
mBytes = new ByteArrayOutputStream((int)(64 * (1 << 10)));
coded = CodedOutputStream.newInstance(mBytes);

// then as protobuf messages come in, i append to the stream
// if the message puts us over the threshold of 64k, we write out what's in
// the buffer and start fresh
private void write(final MessageLite aObj) throws IOException {

  final int aObjSize = aObj.getSerializedSize();
  final int aCurrSize = mBytes.size();
  final int aNewSize = aObjSize + aCurrSize;

  if (aNewSize > THRESHOLD) {
    write();

    mBytes.reset();
  }

  // mTag is initialized in the constructor with the int representing the repeated field
  // in the example from my email, this would be something like MessageType3.TYPE2_FIELD_NUMBER
  coded.writeMessage(mTag, aObj);
  coded.flush();
}

// here's the shortened write method
private void write() throws IOException {
  // mPrototypeAsBytes is created in the constructor from a call like 
  // MessageType3.getDefaultInstance().toByteArray() -- almost always this is
  // a zero length byte array, but i allow for the case that we've set defalut values 
  // on the object we'd like to send
  
  coded.flush();
  final byte[] aBytes = mBytes.toByteArray();

  int sz = CodedOutputStream.computeRawVarint32Size(aBytes.length + mPrototypeAsBytes.length);

  final byte[] size = new byte[sz];
  CodedOutputStream c = CodedOutputStream.newInstance(size);
  c.writeRawVarint32(aBytes.length + mPrototypeAsBytes.length);
  
  byte[] aPayload = Bytes.concat(size, mPrototypeAsBytes, aBytes);
  
  // the rest is ommitted, we take the payload and send it across the wire at this point
  // where on the other end we use the standard mergeFrom to parse the message back into
  // a protobuf message object
}