Calls fun.(item), returning item with any transformations done therein.

Basically, I got tired of not being able to pipe a value into arbitrary positions of other functions.

Examples

iex> ", " |> Item.tap(&Enum.join(1..10, &1))
"1, 2, 3, 4, 5, 6, 7, 8, 9, 10"

iex> false |> Item.tap(&(unless &1, do: "oh!"))
"oh!"

iex> [5, 4, 3, 2, 1] |> hd |> Item.tap(&(&1 * &1))
25

iex> "hello world!" |> Item.tap(&Regex.scan(~r/lo?/, &1))
[["l"], ["lo"], ["l"]]