iex> jwt = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdWQiOiJjYWExOmFjYzpleGFtcGxlLmNvbSIsImV4cCI6MTY3MTkyMjMwMCwiZm9yIjp7fSwic3ViIjoiY2FzMTpuYXJmIn0.N6PV_XAGTjymi1CEfVkKRj433S0XBlTxcevL7VAhTRY"
iex> extract(jwt, :all)
{:ok, %{"alg" => "HS256","typ" => "JWT"}, %{aud: "caa1:acc:example.com", exp: 1671922300, for: %{}, sub: "cas1:narf"}}
iex> extract(jwt, :claims)
{:ok, %{aud: "caa1:acc:example.com", exp: 1671922300, for: %{}, sub: "cas1:narf"}}
iex> extract(jwt, :header)
{:ok, %{"alg" => "HS256","typ" => "JWT"}}
iex> extract("asdf", :all)
{:error, "Invalid JWT, cannot extract claims"}
iex> extract("asdf.asdf.asdf", :all)
{:error, "Unable to decode JWT part: asdf"}