class Aws::Plugins::TransferEncoding::Handler

def call(context)
  if streaming?(context.operation.input)
    # If it's an IO object and not a File / String / String IO
    unless context.http_request.body.respond_to?(:size)
      if requires_length?(context.operation.input)
        # if size of the IO is not available but required
        raise Aws::Errors::MissingContentLength.new
      elsif context.operation['authtype'] == "v4-unsigned-body"
        context.http_request.headers['Transfer-Encoding'] = 'chunked'
      end
    end
  end
  @handler.call(context)
end

def requires_length?(ref)
  payload = ref[:payload_member]
  payload["requiresLength"] || # checking ref and shape
    payload.shape["requiresLength"]
end

def streaming?(ref)
  if payload = ref[:payload_member]
    payload["streaming"] || # checking ref and shape
      payload.shape["streaming"]
  else
    false
  end
end