The review of std.hash package

[Piotr Szturmaj]

Walter Bright wrote:
>
>    auto result = file.byChunk(4096 * 1025).joiner.hash();
>
> The magic is that any input range that produces bytes could be used, and
> that byte producing input range can be hooked up to the input of any
> reducing function.

Suppose you have a callback that will give you blocks of bytes to hash. 
Blocks of bytes come from a socket, but not a blocking one. Instead, 
socket uses eventing mechanism (libevent) to get notifications about its 
readiness.

How would you use the hash API in this situation?