An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

You probably want to test the external provider once, but not necessarily call it for every test that runs.

// error if the server message is invalid.  Calling Step after a conversation
// completes is also an error.
func (x *XDGSCRAMClient) Step(challenge string) (response string, err error) {
	response, err = x.ClientConversation.Step(challenge)
	return
}

// Done returns true if the conversation is completed or has errored.
func (x *XDGSCRAMClient) Done() bool {

    this.closeables = closeables;
  }

  /**
   * Returns a future that finishes when this step does. Calling {@code get()} on the returned
   * future returns {@code null} if the step is successful or throws the same exception that would
   * be thrown by calling {@code finishToFuture().get()} if this were the last step. Calling {@code
   * cancel()} on the returned future has no effect on the {@code ClosingFuture} pipeline.
   *

  @Override
  int hashCode();

  /**
   * Returns a readable string representation of this range set. For example, if this {@code
   * RangeSet} consisted of {@code Range.closed(1, 3)} and {@code Range.greaterThan(4)}, this might
   * return {@code " [1..3](4..+∞)}"}.
   */
  @Override
  String toString();

            // TODO: Maybe this could be simplified by not using the copy infrastructure and just
            // calling the FilterReader ourselves.  We're just taking one file and turning it into another.

            // The order here is important! tokens are inserted by the transformer
            Map<String, Object> parameters = new HashMap<>();

   */
  public static HashCode fromString(String string) {
    checkArgument(
        string.length() >= 2, "input string (%s) must have at least 2 characters", string);
    checkArgument(
        string.length() % 2 == 0,
        "input string (%s) must have an even number of characters",
        string);

    byte[] bytes = new byte[string.length() / 2];
    for (int i = 0; i < string.length(); i += 2) {

    private static final String S2C_SIGN_CONSTANT = "session key to server-to-client signing key magic constant";
    private static final String S2C_SEAL_CONSTANT = "session key to server-to-client sealing key magic constant";

    private static final String C2S_SIGN_CONSTANT = "session key to client-to-server signing key magic constant";

import java.io.IOException;

/**
Do not use this class. Writing to the OutputStream of this type of socket
requires leaving a 4 byte prefix for the NBT header. IOW you must call
write( buf, 4, len ). Calling write( buf, 0, len ) will generate an error.
 */

public class NbtSocket extends Socket {

    private static final int SSN_SRVC_PORT = 139;
    private static final int BUFFER_SIZE = 512;

                    List<String> values = option.getValuesList();
                    for (ListIterator<String> it = values.listIterator(); it.hasNext(); ) {
                        it.set(interpolator.interpolate(it.next()));
                    }
                }
                commandLineBuilder.addOption(option);
            }
            for (String arg : options.commandLine.getArgList()) {

   */
  @Throws(IOException::class)
  fun urls(): MutableIterator<String> {
    return object : MutableIterator<String> {
      private val delegate: MutableIterator<DiskLruCache.Snapshot> = cache.snapshots()
      private var nextUrl: String? = null
      private var canRemove = false

      override fun hasNext(): Boolean {
        if (nextUrl != null) return true