Add Resource.evalTap

[nigredo-tori]

A cross between flatTap and evalMap. Use case - an action returning a temporary resource with custom setup. For me this pattern pops up all the time when writing logic that uses temporary files (create a temporary file, write some data to it, yield the file).

[codecov-io]

Codecov Report

Merging #490 into master will decrease coverage by 0.28%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #490      +/-   ##
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- Coverage   89.81%   89.53%   -0.29%     
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  Files          70       70              
  Lines        2043     2044       +1     
  Branches      213      198      -15     
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- Hits         1835     1830       -5     
- Misses        208      214       +6

[kubukoz]

Not sure if it's worth the effort - consecutive evalTap invocations like evalMap(f).evalMap(g).use(h) are pretty much like use(a => f(a) *> g(a) *> h(a)). But if others feel like this is useful enough to be a new method, then I'm good :)

[nigredo-tori]

consecutive evalTap invocations like evalMap(f).evalMap(g).use(h) are pretty much like use(a => f(a) *> g(a) *> h(a))

This works when you immediately do .use, but .evalTap is useful for more complex cases (like traversing a collection in Resource, or returning a prepared Resource from a function).

[mpilquist]

👍 from me -- fs2 has evalTap as well:

// On Stream[F, O]
def evalTap[F2[x] >: F[x]: Functor](f: O => F2[Unit]): Stream[F2, O] =

[djspiewak]

This is merged into series/1.x, but due to a snafu on my end, we didn't update the base before the merge. So this will eventually land in master, but only after the 1.3 release (soon™).