private val countingSource: CountingSource = CountingSource(source)
  private val source: BufferedSource = countingSource.buffer()

  /** Total bytes read thus far. */
  private val byteCount: Long
    get() = countingSource.bytesRead - source.buffer.size

  /** How many bytes to read before [peekHeader] should return false, or -1L for no limit. */
  private var limit = -1L

            - receive
            - send
            - accept
            - receive_text
            - receive_bytes
            - receive_json
            - iter_text
            - iter_bytes
            - iter_json
            - send_text
            - send_bytes
            - send_json
            - close

When a client disconnects, a `WebSocketDisconnect` exception is raised, you can catch it.

      if (type == TYPE_A || type == TYPE_AAAA) {
        val bytes = ByteArray(length)
        buf.read(bytes)
        result.add(InetAddress.getByAddress(bytes))
      } else {
        buf.skip(length.toLong())
      }
    }

    return result
  }

  @Throws(EOFException::class)
  private fun skipName(source: Buffer) {
    // 0 - 63 bytes
    var length = source.readByte().toInt()

    throw IOException("Cannot buffer entire body for content length: $contentLength")
  }

  val bytes = source().use(consumer)
  val size = sizeMapper(bytes)
  if (contentLength != -1L && contentLength != size.toLong()) {
    throw IOException("Content-Length ($contentLength) and stream length ($size) disagree")
  }
  return bytes
}

internal fun ResponseBody.commonClose() = source().closeQuietly()

  // performed while the lock is held.

  /** The bytes consumed and acknowledged by the stream. */
  val readBytes: WindowCounter = WindowCounter(id)

  /** The total number of bytes produced by the application. */
  var writeBytesTotal = 0L
    internal set

  /** The total number of bytes permitted to be produced by incoming `WINDOW_UPDATE` frame. */

 * prefix are called a 'section'. There are 128 code points per section.
 *
 * Ranges Data (32,612 bytes)
 * ==========================
 *
 * Each entry is 4 bytes, and represents a _range_ of code points that all share a common 14-bit
 * prefix. Entries are sorted by their complete code points.
 *
 * The 4 bytes are named b0, b1, b2 and b3. We also define these supplemental values:
 *
 *  * **b2a**: b2 + 0x80

 * limitations under the License.
 */
package okhttp3.internal.http2.flowcontrol

class WindowCounter(
  val streamId: Int,
) {
  /** The total number of bytes consumed. */
  var total: Long = 0L
    private set

  /** The total number of bytes acknowledged by outgoing `WINDOW_UPDATE` frames. */
  var acknowledged: Long = 0L
    private set

  val unacknowledged: Long
    @Synchronized get() = total - acknowledged

Файлы будут загружены как данные формы.

Если вы объявите тип параметра у *функции операции пути* как `bytes`, то **FastAPI** прочитает файл за вас, и вы получите его содержимое в виде `bytes`.

Следует иметь в виду, что все содержимое будет храниться в памяти. Это хорошо подходит для небольших файлов.

文件作为「表单数据」上传。

如果把*路径操作函数*参数的类型声明为 `bytes`，**FastAPI** 将以 `bytes` 形式读取和接收文件内容。

这种方式把文件的所有内容都存储在内存里，适用于小型文件。

不过，很多情况下，`UploadFile` 更好用。

## 含 `UploadFile` 的文件参数

定义文件参数时使用 `UploadFile`：

```Python hl_lines="12"
{!../../../docs_src/request_files/tutorial001.py!}
```

`UploadFile` 与 `bytes` 相比有更多优势：

* 使用 `spooled` 文件：
    * 存储在内存的文件超出最大上限时，FastAPI 会把文件存入磁盘；

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.tls.internal.der

/**
 * The first two bytes of each value is a header that includes its tag (field ID) and length.
 */
internal data class DerHeader(
  /**
   * Namespace of the tag.
   *
   * This value is encoded in bits 7 and 8 of the first byte of each value.