to.write(buf, 0, r);
      total += r;
    }
    return total;
  }

  /**
   * Copies all bytes from the readable channel to the writable channel. Does not close or flush
   * either channel.
   *
   * @param from the readable channel to read from
   * @param to the writable channel to write to
   * @return the number of bytes copied
   * @throws IOException if an I/O error occurs
   */
  @J2ktIncompatible

      }

    val fileOperator = FileOperator(file!!.channel)
    fileOperator.write(0, header, FILE_HEADER_SIZE)
  }

  @Throws(IOException::class)
  private fun writeMetadata(upstreamSize: Long) {
    val metadataBuffer = Buffer()
    metadataBuffer.write(metadata)

    val fileOperator = FileOperator(file!!.channel)

        assertArgumentNotNull("out", out);

        final FileOutputStream os = OutputStreamUtil.create(out);
        try {
            final FileChannel channel = os.getChannel();
            final ByteBuffer buffer = ByteBuffer.wrap(in);
            return ChannelUtil.write(channel, buffer);
        } finally {
            CloseableUtil.close(os);
        }
    }

    /**

    try {
      RandomAccessFile raf =
          closer.register(new RandomAccessFile(file, mode == MapMode.READ_ONLY ? "r" : "rw"));
      FileChannel channel = closer.register(raf.getChannel());
      return channel.map(mode, 0, size == -1 ? channel.size() : size);
    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**

    try {
      RandomAccessFile raf =
          closer.register(new RandomAccessFile(file, mode == MapMode.READ_ONLY ? "r" : "rw"));
      FileChannel channel = closer.register(raf.getChannel());
      return channel.map(mode, 0, size == -1 ? channel.size() : size);
    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**

- **Network & I/O** (`org.codelibs.core.net`, `org.codelibs.core.nio`) - URL utilities, UUID generation, MIME type detection, and NIO channel operations

## 🚀 Getting Started

### Requirements
- **Java 21 or higher** (Required for modern language features)
- **Maven 3.6+** or **Gradle 7+** for build management

 * href="https://kotlinlang.org/docs/coroutines-guide.html">Kotlin coroutines</a>, including <a
 * href="https://kotlinlang.org/docs/flow.html">Flow</a> and <a
 * href="https://kotlinlang.org/docs/channels.html">Channels</a>. Yet other usages are better served
 * by individual libraries that provide specialized support for particular use cases.
 *
 * <p>Disadvantages of EventBus include:
 *
 * <ul>

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel.MapMode;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel.MapMode;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**