}

	_, ok := kvs.Lookup(Enable)
	// Check if state is required
	_, enableRequired := defaultKVS[subSys].Lookup(Enable)
	if !ok && enableRequired {
		// implicit state "on" if not specified.
		kvs.Set(Enable, EnableOn)
	}

	var currKVS KVS
	ck, ok := c[subSys][tgt]
	if !ok {
		currKVS = defaultKVS[subSys].Clone()
	} else {
		currKVS = ck.Clone()

在这个示例中我们使用的是 OAuth2 的“password”流。

当我们登录自己的应用（很可能还有我们自己的前端）时，这是合适的。

因为我们可以信任它来接收 `username` 和 `password`，毕竟我们掌控它。

但如果你在构建一个 OAuth2 应用，让其它应用来连接（也就是说，你在构建等同于 Facebook、Google、GitHub 等的身份验证提供商），你应该使用其它的流。

最常见的是隐式流（implicit flow）。

最安全的是代码流（authorization code flow），但实现更复杂，需要更多步骤。也因为更复杂，很多提供商最终会建议使用隐式流。

/// note | 注意

每个身份验证提供商常常会用不同的方式给它们的流命名，以融入自己的品牌。

但归根结底，它们实现的都是同一个 OAuth2 标准。

///

  }

  /**
   * Generates test cases for the given combination of scenario and timeouts. For methods that take
   * an explicit timeout value, all of the given timeoutsToUse result in individual test cases. For
   * methods that do not take an explicit timeout value, a single test case is generated only if the
   * implicit timeout of that method matches the given timeoutsToUse. For example, enter() is

@GwtCompatible
public abstract class MultimapBuilder<K0 extends @Nullable Object, V0 extends @Nullable Object> {
  /*
   * Leaving K and V as upper bounds rather than the actual key and value types allows type
   * parameters to be left implicit more often. CacheBuilder uses the same technique.
   */

  private MultimapBuilder() {}

  private static final int DEFAULT_EXPECTED_KEYS = 8;

  /** Uses a hash table to map keys to value collections. */

@GwtCompatible
public abstract class MultimapBuilder<K0 extends @Nullable Object, V0 extends @Nullable Object> {
  /*
   * Leaving K and V as upper bounds rather than the actual key and value types allows type
   * parameters to be left implicit more often. CacheBuilder uses the same technique.
   */

  private MultimapBuilder() {}

  private static final int DEFAULT_EXPECTED_KEYS = 8;

  /** Uses a hash table to map keys to value collections. */

 * evaluation and signaling of conditions. Signaling is entirely <a
 * href="http://en.wikipedia.org/wiki/Monitor_(synchronization)#Implicit_signaling">implicit</a>. By
 * eliminating explicit signaling, this class can guarantee that only one thread is awakened when a
 * condition becomes true (no "signaling storms" due to use of {@link

          // There is no contract one way or another as long as isSubtypeOf() works as expected.
          combined.addAll(asList(typeParam.getBounds()));
          if (combined.size() > 1) { // Object is implicit and only useful if it's the only bound.
            combined.remove(Object.class);
          }
          return super.captureAsTypeVariable(combined.toArray(new Type[0]));
        }
      };
    }

   * Foo<Enum<?>>} according to JLS. See testRecursiveWildcardSubtypeBug() for a real example.
   *
   * <p>It appears that properly handling recursive type bounds in the presence of implicit type
   * bounds is not easy. For now we punt, hoping that this defect should rarely cause issues in real
   * code.
   *
   * @param formalType is {@code Foo<formalType>} a supertype of {@code Foo<T>}?

  }

  /**
   * Generates test cases for the given combination of scenario and timeouts. For methods that take
   * an explicit timeout value, all of the given timeoutsToUse result in individual test cases. For
   * methods that do not take an explicit timeout value, a single test case is generated only if the
   * implicit timeout of that method matches the given timeoutsToUse. For example, enter() is

		if err != nil || len(contentSHA256) == 0 {
			return ErrContentSHA256Mismatch
		}
	}

	// Verify 'Content-Md5' and/or 'X-Amz-Content-Sha256' if present.
	// The verification happens implicit during reading.
	reader, err := hash.NewReader(ctx, r.Body, -1, clientETag.String(), hex.EncodeToString(contentSHA256), -1)
	if err != nil {
		return toAPIErrorCode(ctx, err)
	}
	r.Body = reader
	return ErrNone