For example, in Visual Studio Code, you can:

* Go to the "Debug" panel.
* "Add configuration...".
* Select "Python"
* Run the debugger with the option "`Python: Current File (Integrated Terminal)`".

It will then start the server with your **FastAPI** code, stop at your breakpoints, etc.

Here's how it might look:

<img src="/img/tutorial/debugging/image01.png">

---

If you use Pycharm, you can:

     *
     * @see jcifs.Decodable#decode(byte[], int, int)
     */
    @Override
    public int decode(final byte[] buffer, int bufferIndex, final int len) throws SMBProtocolDecodingException {
        final int start = bufferIndex;
        bufferIndex += 4; // skip idFileSystem

        this.sectPerAlloc = SMBUtil.readInt4(buffer, bufferIndex);
        bufferIndex += 4;

        this.alloc = SMBUtil.readInt4(buffer, bufferIndex);

     */
    @Override
    protected int readBytesWireFormat(final byte[] buffer, int bufferIndex) throws SMBProtocolDecodingException {
        final int start = bufferIndex;
        final int structureSize = SMBUtil.readInt2(buffer, bufferIndex);
        if (structureSize != 24) {
            throw new SMBProtocolDecodingException("Expected structureSize = 24");
        }

    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.Encodable#encode(byte[], int)
     */
    @Override
    public int encode(final byte[] dst, int dstIndex) {
        final int start = dstIndex;

        SMBUtil.writeInt4(this.capabilities, dst, dstIndex);
        dstIndex += 4;

        System.arraycopy(this.clientGuid, 0, dst, dstIndex, 16);
        dstIndex += 16;

          notifyStarted();
        }
      }.start();
    }

    @Override
    protected void doStop() {
      new Thread() {
        @Override
        public void run() {
          Uninterruptibles.sleepUninterruptibly(delay, MILLISECONDS);
          notifyStopped();
        }
      }.start();
    }
  }

  private static class FailStartService extends NoOpService {

  @Throws(IOException::class)
  public fun start(
    inetAddress: InetAddress,
    port: Int,
  ) {
    start(InetSocketAddress(inetAddress, port))
  }

  /**
   * Starts the server and binds to the given socket address.
   *
   * @param socketAddress the socket address to bind the server on
   */
  @Synchronized
  @Throws(IOException::class)
  private fun start(socketAddress: InetSocketAddress) {

        System.arraycopy(fid, 0, buf, pos, 16);
        pos += 16;

        // Calculate offsets relative to start of SMB2 header
        int inputOffsetField = inputCount > 0 ? payloadStart : 0;
        int outputOffsetField = outputCount > 0 ? payloadStart + inputCount : 0;

        // inputOffset (relative to header start)
        SMBUtil.writeInt4(inputOffsetField, buf, pos);
        pos += 4;
        // inputCount

    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.Encodable#encode(byte[], int)
     */
    @Override
    public int encode(final byte[] dst, int dstIndex) {
        final int start = dstIndex;
        SMBUtil.writeInt8(this.timeout, dst, dstIndex);
        dstIndex += 8;
        SMBUtil.writeInt4(this.nameBytes.length, dst, dstIndex);
        dstIndex += 4;

        final int start = dstIndex;
        SMBUtil.writeInt2(24, dst, dstIndex);
        dstIndex += 2;
        dstIndex += 2; // Reserved1
        dstIndex += 4; // Reserved2

        System.arraycopy(this.fileId, 0, dst, dstIndex, 16);
        dstIndex += 16;

        return dstIndex - start;
    }

    /**
     * {@inheritDoc}
     *

        if (len < 20) {
            throw new SMBProtocolDecodingException("Invalid RDMA Transform Capabilities context length: " + len);
        }

        int start = bufferIndex;

        transformCount = SMBUtil.readInt2(buffer, bufferIndex);
        bufferIndex += 2;
        reserved1 = SMBUtil.readInt2(buffer, bufferIndex);
        bufferIndex += 2;