### Use cases: external service { #use-cases-external-service }

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.

* Add more granular permission controls with OAuth2 scopes where needed.
* ...etc.

Nevertheless, you might have a very specific use case where you really need to disable the API docs for some environment (e.g. for production) or depending on configurations from environment variables.

## Conditional OpenAPI from settings and env vars { #conditional-openapi-from-settings-and-env-vars }

 *     notifyAll();
 *   }
 * }
 * }
 *
 * <h3>{@code ReentrantLock}</h3>
 *
 * <p>This version is much more verbose than the {@code synchronized} version, and still suffers
 * from the need for the programmer to remember to use {@code while} instead of {@code if}. However,
 * one advantage is that we can introduce two separate {@code Condition} objects, which allows us to

          //        \   ^__^
          //         \  (oo)\_______
          //            (__)\       )\/\
          //                ||----w |
          //                ||     ||
          // We need to clear the interrupted bit prior to calling park and maintain it in case we
          // wake up spuriously.
          restoreInterruptedBit = Thread.interrupted() || restoreInterruptedBit;
          LockSupport.park(blocker);

ln -s "/usr/include/asm-generic" "/${TARGET}/usr/include/asm-generic"
ln -s "/usr/include/x86_64-linux-gnu/asm" "/${TARGET}/usr/include/asm"

# Symlinks in the binary distribution are set up for installation in /usr, we
# need to fix up all the links to stay within /${TARGET}.
/fixlinks.sh "/${TARGET}"

# Patch to allow non-glibc 2.12 compatible builds to work.
sed -i '54i#define TCP_USER_TIMEOUT 18' "/${TARGET}/usr/include/netinet/tcp.h"

    LoadingCache<String, String> cache =
        CacheBuilder.newBuilder()
            .concurrencyLevel(1)
            .removalListener(listener)
            .build(computingFunction);

    // seed the map, so its segment's count > 0
    cache.getUnchecked("a");
    shouldWait.set(true);

    CountDownLatch computationStarted = new CountDownLatch(1);
    CountDownLatch computationComplete = new CountDownLatch(1);

    LoadingCache<String, String> cache =
        CacheBuilder.newBuilder()
            .concurrencyLevel(1)
            .removalListener(listener)
            .build(computingFunction);

    // seed the map, so its segment's count > 0
    cache.getUnchecked("a");
    shouldWait.set(true);

    CountDownLatch computationStarted = new CountDownLatch(1);
    CountDownLatch computationComplete = new CountDownLatch(1);

)

# Initialize the TensorFlow repository and all dependencies.
#
# The cascade of load() statements and tf_workspace?() calls works around the
# restriction that load() statements need to be at the top of .bzl files.
# E.g. we can not retrieve a new repository with http_archive and then load()
# a macro from that repository in the same file.
load("@//tensorflow:workspace3.bzl", "tf_workspace3")

This is not a limitation of **FastAPI**, it's part of the HTTP protocol.

///

## Recap { #recap }

   * a duration in order to call a legacy API which requires a {@code long, TimeUnit} pair.
   */
  // We use this method only for cases in which we need to decompose to primitives.
  @SuppressWarnings({"GoodTime-ApiWithNumericTimeUnit", "GoodTime-DecomposeToPrimitive"})
  @IgnoreJRERequirement
  static long toNanosSaturated(Duration duration) {