* java.nio.file.Files#newBufferedWriter(java.nio.file.Path, Charset,
   * java.nio.file.OpenOption...)}.
   *
   * @param file the file to write to
   * @param charset the charset used to encode the output stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @return the buffered writer
   */

因此，我们下一步要做的就是添加代码，为从 API 接收回调的*外部 API*存档。

这部分文档在 `/docs` 下的 Swagger API 文档中显示，并且会告诉外部开发者如何构建*外部 API*。

本例没有实现回调本身（只是一行代码），只有文档部分。

/// tip | "提示"

实际的回调只是 HTTP 请求。

实现回调时，要使用 <a href="https://www.encode.io/httpx/" class="external-link" target="_blank">HTTPX</a> 或 <a href="https://requests.readthedocs.io/" class="external-link" target="_blank">Requests</a>。

///

## 编写回调文档代码

应用不执行这部分代码，只是用它来*记录 外部 API* 。

        .build()
    val certificate = heldCertificate.certificate
    assertThat(certificate.getSubjectX500Principal().name).isEqualTo(
      "CN=cash.app,OU=cash",
    )
  }

  /** Confirm golden values of encoded PEMs.  */
  @Test
  fun pems() {
    val keyFactory = KeyFactory.getInstance("RSA")
    val publicKeyBytes =
      (
        "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCApFHhtrLan28q+oMolZuaTfWBA0V5aM" +

🗄 `Response` 🎓 (🎧-🎓) 👆 💚 ⚙️ & 📣 ⚫️ *➡ 🛠️ 👨‍🎨*.

⭕ 📨, 📨 `Response` 🔗 🌅 ⏩ 🌘 🛬 📖.

👉 ↩️ 🔢, FastAPI 🔜 ✔ 🔠 🏬 🔘 & ⚒ 💭 ⚫️ 🎻 ⏮️ 🎻, ⚙️ 🎏 [🎻 🔗 🔢](../tutorial/encoder.md){.internal-link target=_blank} 🔬 🔰. 👉 ⚫️❔ ✔ 👆 📨 **❌ 🎚**, 🖼 💽 🏷.

✋️ 🚥 👆 🎯 👈 🎚 👈 👆 🛬 **🎻 ⏮️ 🎻**, 👆 💪 🚶‍♀️ ⚫️ 🔗 📨 🎓 & ❎ ➕ 🌥 👈 FastAPI 🔜 ✔️ 🚶‍♀️ 👆 📨 🎚 🔘 `jsonable_encoder` ⏭ 🚶‍♀️ ⚫️ 📨 🎓.

//
//	 e1 := MD5(part-1)
//	 e2 := MD5(part-2)
//	...
//	 eN := MD5(part-N)
//
// Then, the ETag of the object is computed as MD5 of all individual
// part checksums. S3 also encodes the number of parts into the ETag
// by appending a -<number-of-parts> at the end:
//
//	ETag := MD5(e1 || e2 || e3 ... || eN) || -N
//
//	For example: ceb8853ddc5086cc4ab9e149f8f09c88-5
//

                    // skip
                    continue;
                }
                try {
                    final String[] permissions = split(getValue(list, 2), ",").get(stream -> stream.map(permissionHelper::encode)
                            .filter(StringUtil::isNotBlank).distinct().toArray(n -> new String[n]));
                    final String[] labels = split(getValue(list, 3), ",")

            final PermissionHelper permissionHelper = ComponentUtil.getPermissionHelper();
            entity.setPermissions(split(form.permissions, "\n").get(stream -> stream.map(s -> permissionHelper.encode(s))
                    .filter(StringUtil::isNotBlank).distinct().toArray(n -> new String[n])));
            entity.setVirtualHosts(split(form.virtualHosts, "\n")

            final PermissionHelper permissionHelper = ComponentUtil.getPermissionHelper();
            entity.setPermissions(split(form.permissions, "\n").get(stream -> stream.map(s -> permissionHelper.encode(s))
                    .filter(StringUtil::isNotBlank).distinct().toArray(n -> new String[n])));
            entity.setVirtualHosts(split(form.virtualHosts, "\n")

  }

  public void testToString() {
    byte[] data = new byte[] {127, -128, 5, -1, 14};
    assertEquals("7f8005ff0e", HashCode.fromBytes(data).toString());
    assertEquals("7f8005ff0e", base16().lowerCase().encode(data));
  }

  public void testHashCode_nulls() throws Exception {
    sanityTester().testNulls();
  }

  public void testHashCode_equalsAndSerializable() throws Exception {

        NdrBuffer buf = new NdrBuffer(out, 0);

        msg.flags = DCERPC_FIRST_FRAG | DCERPC_LAST_FRAG;
        msg.call_id = call_id.incrementAndGet();

        msg.encode(buf);

        if ( this.securityProvider != null ) {
            buf.setIndex(0);
            this.securityProvider.wrap(buf);
        }
        return buf;
    }


    /**
     *