为什么读取文件占用整个文件的内存？

我这样做:

import qualified Data.ByteString.Lazy.Char8 as BS

main :: IO ()
main = do
    let filename = "sample.txt"    
    text <- BS.readFile filename
    let res = BS.take 1000 $ text
    print res

当我通过分析运行它时,它给了我:

162,048 bytes allocated in the heap
2,472 bytes copied during GC
59,688 bytes maximum residency (1 sample(s))
22,232 bytes maximum slop
156 MB total memory in use (0 MB lost due to fragmentation)

我读的文件大约是50K字节.为什么需要60K字节的内存(最大驻留时间)？我也尝试过String和Lazy文本.这是相同的图片.我认为Haskell在某种程度上是将整个文件读入内存或只是分配与文件长一样多的内存.我怎么能阻止这个？我想从它只读N字节,不想浪费这么多的内存.