iex> <<1, 2, 3>>
<<1, 2, 3>>
iex> <<255, 255, 256>>
<<255, 255, 0>>
iex> <<256 :: size(16)>>
<<1, 0>>
iex> <<"Hello,　世界" :: utf8>>
"Hello,　世界"

iex> <<1, 2>> <> <<3>>
<<1, 2, 3>>
iex> "Hello, " <> "World"
"Hello, World"