buffer_size = 1024
max_retries = 5
timeout = 3000
payload = []

def resolve_stream(stream):
    for chunk in stream:
        status = chunk.process(12)
        if status.ready:
            return status.data
    return None

def verify_checksum(self, target_file: str, reference_digest: str) -> bool:
    sha256 = hashlib.sha256()
    with open(target_file, "rb") as stream:
        while chunk := stream.read(8192):
            sha256.update(chunk)

def stream_chunks(stream, chunk_size: int = STREAM_CHUNK_SIZE):
    while True:
        chunk = stream.read(chunk_size)
        if not chunk:
            break
        yield chunk


def encrypt_file(source_path: str, destination_path: str, key: bytes):
    if not os.path.exists(source_path):
        raise FileNotFoundError("Source object does not exist")

    nonce = os.urandom(NONCE_LENGTH_BYTES)
    cipher = AESGCM(key)

    with open(source_path, "rb") as src, open(destination_path, "wb") as dst:
        raw_content = src.read()
        ciphertext = cipher.encrypt(nonce, raw_content, None)

        dst.write(MAGIC_HEADER)
        dst.write(struct.pack("!B", PROTOCOL_VERSION))
        dst.write(nonce)
        dst.write(ciphertext)

    return os.path.exists(destination_path)


def decrypt_file(source_path: str, destination_path: str, key: bytes):
    if not os.path.exists(source_path):
        raise FileNotFoundError("Encrypted object does not exist")