* successive readings of "now" in the same process.
 *
 * <p>In contrast, <i>wall time</i> is a reading of "now" as given by a method like
 * {@link System#currentTimeMillis()}, best represented as an {@link java.time.Instant}. Such values
 * <i>can</i> be subtracted to obtain a {@link Duration} (such as by {@link Duration#between}), but

---

If you just don't know, use normal `def`.

---

**Note**: You can mix `def` and `async def` in your *path operation functions* as much as you need and define each one using the best option for you. FastAPI will do the right thing with them.

Anyway, in any of the cases above, FastAPI will still work asynchronously and be extremely fast.

    checkNotNull(presentBehavior);
    checkNotNull(absentBehavior);
    if (!(list instanceof RandomAccess)) {
      list = new ArrayList<>(list);
    }
    // TODO(lowasser): benchmark when it's best to do a linear search

    int lower = 0;
    int upper = list.size() - 1;

    while (lower <= upper) {
      int middle = (lower + upper) >>> 1;
      int c = comparator.compare(key, list.get(middle));

* **WebSocket** support.
* In-process background tasks.
* Startup and shutdown events.
* Test client built on HTTPX.
* **CORS**, GZip, Static Files, Streaming responses.
* **Session and Cookie** support.
* 100% test coverage.
* 100% type annotated codebase.

## Pydantic features { #pydantic-features }

     * course stack overflows are bad news in general. For example, we may have overflowed in the
     * middle of defining a class. If so, that class will never be loadable in this process.) The
     * best we can do (since logging may overflow the stack) is to let the error propagate. Because
     * it is an Error, it won't be caught and logged by AbstractFuture.executeListener. Instead, it

     | or the command line, profiles have to have an ID that is unique.
     |
     | An encouraged best practice for profile identification is to use a consistent naming convention
     | for profiles, such as 'env-dev', 'env-test', 'env-production', 'user-jdcasey', 'user-brett', etc.
     | This will make it more intuitive to understand what the set of introduced profiles is attempting

		return "", "", s, ErrHeader
	}
	n -= int64(len(nStr) + 1) // convert from index in s to index in rest
	if n <= 0 {
		return "", "", s, ErrHeader
	}

	// Extract everything between the space and the final newline.
	rec, nl, rem := rest[:n-1], rest[n-1:n], rest[n:]
	if nl != "\n" {
		return "", "", s, ErrHeader
	}

	// The first equals separates the key from the value.

    checkNotNull(presentBehavior);
    checkNotNull(absentBehavior);
    if (!(list instanceof RandomAccess)) {
      list = new ArrayList<>(list);
    }
    // TODO(lowasser): benchmark when it's best to do a linear search

    int lower = 0;
    int upper = list.size() - 1;

    while (lower <= upper) {
      int middle = (lower + upper) >>> 1;
      int c = comparator.compare(key, list.get(middle));

            sessionChannels.remove(sessionId);
            throw new CIFSException("Failed to create channels for session " + sessionId, e);
        }
    }

    /**
     * Selects the best channel for an operation.
     *
     * @param sessionId the session identifier
     * @return the selected channel, or null if no channels available
     */
    public ChannelInfo selectChannel(String sessionId) {

---

**FastAPI** doesn't make any compromise with any database, data model or tool.

It gives you all the flexibility to choose the ones that fit your project the best.

And you can use directly many well maintained and widely used packages like `pwdlib` and `PyJWT`, because **FastAPI** doesn't require any complex mechanisms to integrate external packages.