# History, Design and Future { #history-design-and-future }

Some time ago, [a **FastAPI** user asked](https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920):

> What’s the history of this project? It seems to have come from nowhere to awesome in a few weeks [...]

Here's a little bit of that history.

## Alternatives { #alternatives }

| DurationSeconds | Integer | No       | Duration of validity of generated credentials. Must be at least 900. |

The validity duration of the generated STS credentials is the minimum of the `DurationSeconds` parameter (if passed) and the validity duration returned by the Identity Management Plugin.

## API Response

            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header X-NginX-Proxy true;

            # This is necessary to pass the correct IP to be hashed
            real_ip_header X-Real-IP;

            proxy_connect_timeout 300;
            
            # To support websocket
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;

import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/** A regex pattern implementation which is backed by the {@link Pattern}. */
@GwtIncompatible
final class JdkPattern extends CommonPattern implements Serializable {
  private final Pattern pattern;

  JdkPattern(Pattern pattern) {

import com.google.common.annotations.VisibleForTesting;
import java.util.Spliterator;
import java.util.Spliterators;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link ImmutableList} backed by a simple array.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class RegularImmutableList<E> extends ImmutableList<E> {

   * CacheBuilder#softValues}.
   */
  COLLECTED {
    @Override
    boolean wasEvicted() {
      return true;
    }
  },

  /**
   * The entry's expiration timestamp has passed. This can occur when using {@link
   * CacheBuilder#expireAfterWrite} or {@link CacheBuilder#expireAfterAccess}.
   */
  EXPIRED {
    @Override
    boolean wasEvicted() {
      return true;
    }
  },

  ) {}

  /**
   * Invoked when a call no longer uses a connection.
   */
  open fun connectionReleased(
    connection: Connection,
    call: Call,
  ) {}

  /**
   * Invoked when a connection is marked for no new exchanges.
   */
  open fun noNewExchanges(connection: Connection) {}

  companion object {
    val NONE: ConnectionListener = object : ConnectionListener() {}
  }

 * good reference implementation. As with {@code IteratorTester}, a concrete subclass must provide
 * target iterators on demand. It also requires three additional constructor parameters: {@code
 * elementsToInsert}, the elements to be passed to {@code set()} and {@code add()} calls; {@code
 * features}, the features supported by the iterator; and {@code expectedElements}, the elements the
 * iterator should return in order.
 *

 * limitations under the License.
 */

package com.google.common.graph;

import java.util.Set;

/**
 * A class to allow {@link Graph} implementations to be backed by a {@link BaseGraph}. This is not
 * currently planned to be released as a general-purpose forwarding class.
 *
 * @author James Sexton
 */
abstract class ForwardingGraph<N> extends AbstractGraph<N> {

import com.google.common.annotations.J2ktIncompatible;
import org.jspecify.annotations.Nullable;

/**
 * An {@link ImmutableAsList} implementation specialized for when the delegate collection is already
 * backed by an {@code ImmutableList} or array.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace, not default serialization