Typed Inttegro domain value.
@type t() :: %Inttegro.Products.ProductDimensionsCustom{ details: %{optional(String.t()) => String.t()} | nil, size: number() | nil, size_unit: String.t() | nil }
@spec from_map(map()) :: t()
@spec new!(map() | keyword()) :: t()
@spec to_map(t()) :: map()