Calculates the sha from the streaming chunk.
add_bytes_to_hash( any(), atom() | pid() | {atom(), any()} | {:via, atom(), any()} ) :: any()
get_hash(atom() | pid() | {atom(), any()} | {:via, atom(), any()}) :: any()
start_link() :: {:error, any()} | {:ok, pid()}
stop(atom() | pid() | {atom(), any()} | {:via, atom(), any()}) :: :ok