get_block() request very slooow.

I benchmarked dshackle and found that get_block (by number or by hash) and with included transactions is terribly slow.

Here are the average results for last 50 blocks:
`Block average response time:
dshackle on node: 1526.1953592300415 ms
dshackle on local machine: 1431.77649974823 ms
node: 135.94377040863037 ms`

Other calls, like block.latest, get_transaction_receipt or getBalance return expected results (ie. add few ms latency).
Can somebody explain why getBlock is so slow and how to tackle the problem?

edit: get_block call without transactions is fast as expected.

Thnx,
Tomi