class ActionController::Streaming::Body

def each(&block)

the element in chunked encoding.
For each element yielded by the response body, yield 
def each(&block)
  term = TERM
  @body.each do |chunk|
    size = chunk.bytesize
    next if size == 0
    yield [size.to_s(16), term, chunk.b, term].join
  end
  yield TAIL
  yield term
end