-3px;\n}\n\n.user-block.user-block-sm img {\n  width: 1.875rem;\n  height: 1.875rem;\n}\n\n.user-block.user-block-sm .username,\n.user-block.user-block-sm .description,\n.user-block.user-block-sm .comment {\n  margin-left: 40px;\n}\n\n.user-block.user-block-sm .username {\n  font-size: 14px;\n}\n\n.img-sm,\n.img-md,\n.img-lg {\n  float: left;\n}\n\n.img-sm {\n  height: 1.875rem;\n  width: 1.875rem;\n}\n\n.img-sm + .img-push {\n  margin-left: 2.5rem;\n}\n\n.img-md {\n  width: 3.75rem;\n  height: 3.75rem;\n}\n\n.img-md...

   * a duration in order to call a legacy API which requires a {@code long, TimeUnit} pair.
   */
  static long toNanosSaturated(Duration duration) {
    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {

   * then:
   *
   * <ul>
   *   <li>{@code isDone()} must return {@code true}
   *   <li>{@code isCancelled()} must return {@code false}
   *   <li>{@code get()} must not block, and it must throw an {@code ExecutionException} with the
   *       return value of this method as its cause
   * </ul>
   */
  public static
      Throwable

It is also built to work as a future reference so you can come back and see exactly what you need.

## Run the code { #run-the-code }

All the code blocks can be copied and used directly (they are actually tested Python files).

To run any of the examples, copy the code to a file `main.py`, and start `fastapi dev`:

<div class="termy">

```console

func EncryptRequest(content io.Reader, r *http.Request, bucket, object string, metadata map[string]string) (io.Reader, crypto.ObjectKey, error) {
	if r.ContentLength > encryptBufferThreshold {
		// The encryption reads in blocks of 64KB.
		// We add a buffer on bigger files to reduce the number of syscalls upstream.
		content = bufio.NewReaderSize(content, encryptBufferSize)
	}

	var (
		key   []byte
		keyID string

/*
 * Copyright (c) 2025 Block, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright (C) 2025 Block, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

 * These constants represent standard Windows error codes returned by SMB servers.
 */
public interface WinError {

    /*
     * Don't bother to edit this. Everything within the interface
     * block is automatically generated from the ntstatus package.
     */

    /** The operation completed successfully */
    int ERROR_SUCCESS = 0;
    /** Access is denied */
    int ERROR_ACCESS_DENIED = 5;

 * These constants represent standard Windows error codes returned by SMB servers.
 */
public interface WinError {

    /* Don't bother to edit this. Everthing within the interface
     * block is automatically generated from the ntstatus package.
     */

    /** The operation completed successfully */
    int ERROR_SUCCESS = 0;
    /** Access is denied */
    int ERROR_ACCESS_DENIED = 5;

Calls are executed in one of two ways:

 * **Synchronous:** your thread blocks until the response is readable.
 * **Asynchronous:** you enqueue the request on any thread, and get [called back](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-callback/) on another thread when the response is readable.