# Ztunnel

This document provides an overview of the architecture and design decisions around Ztunnel, the node-proxy component in ambient mode.

## Background and motivation

Motivations to implement ztunnel generally came from two areas.

First, and most importantly, it serves as a means to implement the real goal: waypoints.

		if _, loaded := c.outgoing.LoadOrStore(client.MuxID, client); client.MuxID != 0 && !loaded {
			if debugReqs {
				_, found := c.outgoing.Load(client.MuxID)
				fmt.Println(client.MuxID, c.String(), "Connection.newMuxClient: RELOADED MUX. loaded:", loaded, "found:", found)
			}
			return client, nil
		}
		client.MuxID = atomic.AddUint64(&c.NextID, 1)
	}
}

  }

  private Joiner(Joiner prototype) {
    this.separator = prototype.separator;
  }

  /*
   * In this file, we use <? extends @Nullable Object> instead of <?> to work around a Kotlin bug
   * (see b/189937072 until we file a bug against Kotlin itself). (The two should be equivalent, so
   * we normally prefer the shorter one.)
   */

  /**

import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.Arrays;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Wrapper around either a {@link Method} or a {@link Constructor}. Convenience API is provided to
 * make common reflective operation easier to deal with, such as {@link #isPublic}, {@link
 * #getParameters} etc.
 *

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * GWT emulated version of {@link com.google.common.collect.ImmutableSortedMap}. It's a thin wrapper
 * around a {@link java.util.TreeMap}.
 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
public final class ImmutableSortedMap<K, V> extends ForwardingImmutableMap<K, V>
    implements SortedMap<K, V> {

    sort(insertionOrder, Helpers.entryComparator(keyComparator));
    return insertionOrder;
  }

  /**
   * Private replacement for {@link com.google.gwt.user.client.rpc.GwtTransient} to work around
   * build-system quirks.
   */
  private @interface GwtTransient {}

  /**
   * Compares strings in natural order except that null comes immediately before a given value. This

    executor.execute(new SleepTask(1000));
    executor.shutdown();
    awaitTerminationUninterruptibly(executor);
    assertTrue(executor.isTerminated());
    assertInterrupted();
  }

  /**
   * Wrapper around {@link Stopwatch} which also contains an "expected completion time." Creating a
   * {@code Completion} starts the underlying stopwatch.
   */
  private static final class Completion {
    final Stopwatch stopwatch;

    executor.execute(new SleepTask(1000));
    executor.shutdown();
    awaitTerminationUninterruptibly(executor);
    assertTrue(executor.isTerminated());
    assertInterrupted();
  }

  /**
   * Wrapper around {@link Stopwatch} which also contains an "expected completion time." Creating a
   * {@code Completion} starts the underlying stopwatch.
   */
  private static final class Completion {
    final Stopwatch stopwatch;

    String[] array = new String[] {null};
    assertThrows(NullPointerException.class, () -> ImmutableSortedMultiset.copyOf(array));
  }

  public void testCopyOf_collection_empty() {
    // "<String>" is required to work around a javac 1.5 bug.
    Collection<String> c = MinimalCollection.<String>of();
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(c);
    assertTrue(multiset.isEmpty());
  }

  }

  private Joiner(Joiner prototype) {
    this.separator = prototype.separator;
  }

  /*
   * In this file, we use <? extends @Nullable Object> instead of <?> to work around a Kotlin bug
   * (see b/189937072 until we file a bug against Kotlin itself). (The two should be equivalent, so
   * we normally prefer the shorter one.)
   */

  /**