You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: datasink.go
    path of file: ./repos/beam/sdks/go/pkg/beam/core/runtime/exec
    
    the code of the file until where you have to start completion: // Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements.  See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License.  You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissio
    
func (n *DataSink) ProcessElement(ctx context.Context, value *FullValue, values ...ReStream) error {
	// Marshal the pieces into a temporary buffer since they must be transmitted on FnAPI as a single
	// unit.
	var b bytes.Buffer

	if err := EncodeWindowedValueHeader(n.wEnc, value.Windows, value.Timestamp, value.Pane, &b); err != nil {
		return err
	}
	if err := n.enc.Encode(value, &b); err != nil {
		return errors.WithContextf(err, "encoding element %v with coder %v", value, n.Coder)
	}
	byteCount, err := n.w.Write(b.Bytes())
	if err != nil {
		return err
	}
	// TODO[BEAM-6374): Properly handle the multiplex and flatten cases.
	// Right now we just stop datasink collection.
	if n.PCol != nil {
		atomic.AddInt64(&n.PCol.bundleElementCount, 1)
		n.PCol.addSize(int64(byteCount))
	}
	return nil
}