private val connectionUser: ConnectionUser,
  private val fastFallback: Boolean,
) {
  // State for negotiating the next proxy to use.
  private var proxies = emptyList<Proxy>()
  private var nextProxyIndex: Int = 0

  // State for negotiating the next socket address to use.
  private var inetSocketAddresses = emptyList<InetSocketAddress>()

  // State for negotiating failed routes

      }
    }

    // Call the next interceptor in the chain.
    val next = copy(index = index + 1, request = request)
    val interceptor = interceptors[index]

    @Suppress("USELESS_ELVIS")
    val response =
      interceptor.intercept(next) ?: throw NullPointerException(
        "interceptor $interceptor returned null",
      )

The main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} should be enough to give you a tour through all the main features of **FastAPI**.

In the next sections you will see other options, configurations, and additional features.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

            processor.invoke(symbol.fir)
            ProcessorAction.NEXT
        }
        is FirProperty -> processOverriddenProperties(declaration.symbol) { symbol ->
            processor.invoke(symbol.fir)
            ProcessorAction.NEXT
        }
        else -> ProcessorAction.STOP
    }

    private fun FirTypeScope.processDirectOverriddenDeclarations(

): List<T> {
  val ia = a.iterator()
  val ib = b.iterator()

  return buildList {
    while (ia.hasNext() || ib.hasNext()) {
      if (ia.hasNext()) {
        add(ia.next())
      }
      if (ib.hasNext()) {
        add(ib.next())
      }
    }
  }
}

// TODO check read only options for creating lists
public fun <T> List<T>.readOnly() = this.toList()

    assertThat(actualUrls).containsExactly(*expectedUrls)
  }

  fun finishJob(url: String) {
    val i = calls.iterator()
    while (i.hasNext()) {
      val call = i.next()
      if (call.request.url.toString() == url) {
        i.remove()
        dispatcherTest.dispatcher.finishedAccessor(call)
        return
      }
    }
    throw AssertionError("No such job: $url")
  }

## ساخت یک میان افزار

برای ایجاد یک میان‌افزار، از دکوریتور `@app.middleware("http")` در بالای یک تابع استفاده می‌شود.

تابع میان افزار دریافت می کند:
* `درخواست`
* تابع `call_next` که `درخواست` را به عنوان پارامتر دریافت می کند
    * این تابع `درخواست` را به *path operation* مربوطه ارسال می کند.
    * سپس `پاسخ` تولید شده توسط *path operation* مربوطه را برمی‌گرداند.

```Python hl_lines="18-20"
{!../../../docs_src/sql_databases_peewee/sql_app/main.py!}
```

For the **next request**, as we will reset that context variable again in the `async` dependency `reset_db_state()` and then create a new connection in the `get_db()` dependency, that new request will have its own database state (connection, transactions, etc).

        ":tf_buffer_internal",
        ":tf_status",
        ":tf_status_helper",
        ":tf_tensor_internal",
        "//tensorflow/core/common_runtime/next_pluggable_device/c:tf_rendezvous_c_api",
        "//tensorflow/core/common_runtime/next_pluggable_device/c:tf_rendezvous_c_api_internal",
        "//tensorflow/core/platform:notification",
        "@com_google_absl//absl/status",
        "@com_google_absl//absl/strings",

// 			"aOption":"foo",
// 		},
// 	}
//
// So what happens? Decode first uses json or yaml to unmarshal the serialized data into
// your external MyAPIObject. That causes the raw JSON to be stored, but not unpacked.
// The next step is to copy (using pkg/conversion) into the internal struct. The runtime
// package's DefaultScheme has conversion functions installed which will unpack the