assertArgumentNotNull("channel", channel);

        try {
            return channel.size();
        } catch (final IOException e) {
            throw new IORuntimeException(e);
        }
    }

    /**
     * Reads the contents of the file channel into a byte buffer.
     *
     * @param channel
     *            The file channel. Must not be {@literal null}.
     * @param buffer

            listOf(Channel, Standard).flatMap { socketMode ->
              listOf(DISABLED, STANDARD).map { tlsExtensionMode ->
                TlsInstance(provider, protocol, tlsVersion, socketMode, tlsExtensionMode)
              }
            }
          }
        }
      } + Channel + Standard
  }
}

sealed class SocketMode

object Channel : SocketMode() {

      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

        final FileInputStream is = InputStreamUtil.create(file);
        try {
            final FileChannel channel = is.getChannel();
            final ByteBuffer buffer = ByteBuffer.allocate((int) ChannelUtil.size(channel));
            ChannelUtil.read(channel, buffer);
            return buffer.array();
        } finally {
            CloseableUtil.close(is);
        }
    }

    /**

      }

    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();
    }
  }

  /**

  @Throws(IOException::class)
  override fun sendUrgentData(value: Int) {
    delegate!!.sendUrgentData(value)
  }

  override fun getChannel(): SocketChannel = delegate!!.channel

  override fun getHandshakeSession(): SSLSession = delegate!!.handshakeSession

  override fun getApplicationProtocol(): String = delegate!!.applicationProtocol

- **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