CSV::Parser::InputsScanner#read_chunk

# File tmp/rubies/ruby-3.3.0/lib/csv/parser.rb, line 285
def read_chunk
  return false if @last_scanner

  adjust_last_keep

  input = @inputs.first
  case input
  when StringIO
    string = input.read
    raise InvalidEncoding unless string.valid_encoding?
    # trace(__method__, :stringio, string)
    @scanner = StringScanner.new(string)
    @inputs.shift
    @last_scanner = @inputs.empty?
    true
  else
    chunk = input.gets(@row_separator, @chunk_size)
    if chunk
      raise InvalidEncoding unless chunk.valid_encoding?
      # trace(__method__, :chunk, chunk)
      @scanner = StringScanner.new(chunk)
      if input.respond_to?(:eof?) and input.eof?
        @inputs.shift
        @last_scanner = @inputs.empty?
      end
      true
    else
      # trace(__method__, :no_chunk)
      @scanner = StringScanner.new("".encode(@encoding))
      @inputs.shift
      @last_scanner = @inputs.empty?
      if @last_scanner
        false
      else
        read_chunk
      end
    end
  end
end