After working on rust for almost 2 years, I finally reached a point where I can see (and wait for) a few improvements. First is completing the `impl Trait` sag

After working on rust for almost 2 years, I finally reached a point where I can see (and wait for) a few improvements. First is completing the `impl Trait` saga. I see a couple of areas where I'm obliged to box a trait to get the compiler to accept the code. Not the end of the world. Second is allowing conversions of AsyncRead to Stream. currently you have to do a weird dance to get chunks of tokio::File as Stream of Bytes. I think something is missing. Something as straightforward should be easy even if it's not part of std. Last, is adding support for Generators and their transformation into Stream. Then, getting a Stream of Val would be as simple as `yield val` in a function. I'm sure their current API on nightly will change before it's merged to stable rust, and I even hope they will get rid of the "return type" in gens (it complicates things a little bit). After that last point, I can see Rust replacing python for most of the data prep work we have in data science/AI.