### Async Context Manager { #async-context-manager }

If you check, the function is decorated with an `@asynccontextmanager`.

That converts the function into something called an "**async context manager**".

{* ../../docs_src/events/tutorial003_py39.py hl[1,13] *}

    private final ChannelManager manager;
    private final ExecutorService executor;
    private final ConcurrentMap<String, FailoverState> failoverStates;

    /**
     * Create channel failover handler
     *
     * @param manager channel manager
     */
    public ChannelFailover(ChannelManager manager) {
        this.manager = manager;
        this.executor = Executors.newCachedThreadPool(r -> {

manager = ConnectionManager()


@app.get("/")
async def get():
    return HTMLResponse(html)


@app.websocket("/ws/{client_id}")
async def websocket_endpoint(websocket: WebSocket, client_id: int):
    await manager.connect(websocket)
    try:
        while True:
            data = await websocket.receive_text()

    private final ImmutableList<Range<C>> ranges;

    SerializedForm(ImmutableList<Range<C>> ranges) {
      this.ranges = ranges;
    }

    Object readResolve() {
      if (ranges.isEmpty()) {
        return of();
      } else if (ranges.equals(ImmutableList.of(Range.all()))) {
        return all();
      } else {
        return new ImmutableRangeSet<C>(ranges);
      }
    }
  }

    assertThat(compactTable.ranges.length).isLessThan((1 shl 14) * 4)

    // Less than 16,384 chars, because we index on a 14-bit index in the ranges table.
    assertThat(compactTable.mappings.length).isLessThan(1 shl 14)

    // Confirm the data strings are ASCII.
    for (dataString in listOf<String>(compactTable.sections, compactTable.ranges)) {
      for (codePoint in dataString.codePoints()) {

/**
 * A set comprising zero or more {@linkplain Range#isEmpty nonempty}, {@linkplain
 * Range#isConnected(Range) disconnected} ranges of type {@code C}.
 *
 * <p>Implementations that choose to support the {@link #add(Range)} operation are required to
 * ignore empty ranges and coalesce connected ranges. For example:
 *
 * {@snippet :
 * RangeSet<Integer> rangeSet = TreeRangeSet.create();
 * rangeSet.add(Range.closed(1, 10)); // {[1, 10]}

      <role>org.apache.maven.wagon.Wagon</role>
      <role-hint>a</role-hint>
      <implementation>org.apache.maven.artifact.manager.WagonA</implementation>
    </component>
    <component>
      <role>org.apache.maven.wagon.Wagon</role>
      <role-hint>b1</role-hint>
      <implementation>org.apache.maven.artifact.manager.WagonB</implementation>
    </component>
    <component>
      <role>org.apache.maven.wagon.Wagon</role>

    }
    
    public ChannelLoadBalancer(ChannelManager manager) {
        this.manager = manager;
        this.strategy = LoadBalancingStrategy.ADAPTIVE;
    }
    
    public ChannelInfo selectChannel(SMBMessage message) {
        Collection<ChannelInfo> availableChannels = manager.getHealthyChannels();
        
        if (availableChannels.isEmpty()) {

 *
 * b0b1s7 is the section prefix. If a section is omitted, that means its ranges data exactly matches
 * that of the preceding section.
 *
 * b2b3s2 is the offset into the ranges data. It is shifted by 2 because ranges are 4-byte aligned.
 *
 * Mappings Data (4,719 bytes)
 * ===========================
 *
 * This is UTF-8 character data. It is indexed into by b2b3 in the ranges dataset.
 *
 * Mappings may overlap.
 *
 * ASCII-Only

    /**
     * Create a new handle reconnector
     * @param manager the persistent handle manager
     */
    public HandleReconnector(PersistentHandleManager manager) {
        this(manager, 3, 1000);
    }

    /**
     * Create a new handle reconnector with custom settings
     * @param manager the persistent handle manager
     * @param maxRetries maximum number of retry attempts