@spec add_part(t(), Multipart.Part.t()) :: t()

Adds a part to the Multipart message.

@spec body_binary(t()) :: binary()

Returns a binary of the Multipart message body.

This uses body_stream/1 under the hood.

@spec body_stream(t()) :: Enum.t()

Returns a Stream of the Multipart message body.

@spec content_length(t()) :: pos_integer()

Returns the length of the Multipart message in bytes.

It uses the content_length property in each of the message parts to calculate the length of the multipart message without reading the entire body into memory. content_length is set on the Multipart.Part by the constructor functions when possible, such as when the in-memory binary or the file on disk can be inspected.

This will throw an error if any of the parts does not have content_length defined.

@spec content_type(t(), String.t()) :: String.t()

Returns the Content-Type header for the Multipart message.

iex> multipart = Multipart.new("==abc123==")
iex> Multipart.content_type(multipart, "multipart/mixed")
"multipart/mixed; boundary=\"==abc123==\""

@spec new(String.t()) :: t()

Create a new Multipart request.

Pass in the boundary as the first argument to set it explicitly, otherwise it will default to a random 16 character alphanumeric string padded by == on either side.