Map<Class<? extends @NonNull B>, B> backingMap) {
    return new MutableClassToInstanceMap<>(backingMap);
  }

  private final Map<Class<? extends @NonNull B>, B> delegate;

  private MutableClassToInstanceMap(Map<Class<? extends @NonNull B>, B> delegate) {
    this.delegate = checkNotNull(delegate);
  }

  @Override
  protected Map<Class<? extends @NonNull B>, B> delegate() {
    return delegate;
  }

      Class<? super @NonNull E> type, E... contents) {
    return new MinimalCollection<>(type, true, contents);
  }

  private final E[] contents;
  private final Class<? super @NonNull E> type;
  private final boolean allowNulls;

  // Package-private so that it can be extended.
  MinimalCollection(Class<? super @NonNull E> type, boolean allowNulls, E... contents) {

   *
   * <p><b>{@code Stream} equivalent:</b> {@code stream.filter(predicate).findFirst()}.
   */
  public final Optional<@NonNull E> firstMatch(Predicate<? super E> predicate) {
    // Unsafe, but we can't do much about it now.
    return Iterables.<@NonNull E>tryFind((Iterable<@NonNull E>) getDelegate(), predicate);
  }

  /**
   * Returns a fluent iterable that applies {@code function} to each element of this fluent

   *
   * <p><b>{@code Stream} equivalent:</b> {@code stream.filter(predicate).findFirst()}.
   */
  public final Optional<@NonNull E> firstMatch(Predicate<? super E> predicate) {
    // Unsafe, but we can't do much about it now.
    return Iterables.<@NonNull E>tryFind((Iterable<@NonNull E>) getDelegate(), predicate);
  }

  /**
   * Returns a fluent iterable that applies {@code function} to each element of this fluent

      Class<? super @NonNull E> type, E... contents) {
    return new MinimalCollection<>(type, true, contents);
  }

  private final E[] contents;
  private final Class<? super @NonNull E> type;
  private final boolean allowNulls;

  // Package-private so that it can be extended.
  MinimalCollection(Class<? super @NonNull E> type, boolean allowNulls, E... contents) {

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to object arrays.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to object arrays.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible

import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Supplier;
import java.util.stream.Collector;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * Collectors not present in {@code java.util.stream.Collectors} that are not otherwise associated
 * with a {@code com.google.common} type.
 *

import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Supplier;
import java.util.stream.Collector;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * Collectors not present in {@code java.util.stream.Collectors} that are not otherwise associated
 * with a {@code com.google.common} type.
 *

        new ListFuture<V>(ImmutableList.copyOf(futures), true);
    // allAsList ensures that it fills the output list with V instances.
    @SuppressWarnings("nullness")
    ListenableFuture<List<V>> nonNull = nullable;
    return nonNull;
  }

  /**
   * Creates a new {@code ListenableFuture} whose value is a list containing the values of all its
   * input futures, if all succeed.
   *