document EASY_HOOK and setopt (#215)

* add documentation to setopt

* document EASY_HOOK

Author: lamdor

src/Curl/Curl.jl

@@ -93,8 +93,19 @@ function with_handle(f, handle::Union{Multi, Easy})
     end
 end
 
+"""
+    setopt(easy::Easy, option::Integer, value)
+
+Sets options on libcurl's "easy" interface. `option` corresponds to libcurl options on https://curl.se/libcurl/c/curl_easy_setopt.html
+"""
 setopt(easy::Easy, option::Integer, value) =
     @check curl_easy_setopt(easy.handle, option, value)
+
+"""
+    setopt(multi::Multi, option::Integer, value)
+
+Sets options on libcurl's "multi" interface. `option` corresponds to libcurl options on https://curl.se/libcurl/c/curl_multi_setopt.html
+"""
 setopt(multi::Multi, option::Integer, value) =
     @check curl_multi_setopt(multi.handle, option, value)
 

src/Downloads.jl

@@ -63,6 +63,15 @@ end
 
 const DOWNLOAD_LOCK = ReentrantLock()
 const DOWNLOADER = Ref{Union{Downloader, Nothing}}(nothing)
+
+"""
+`EASY_HOOK` is a modifable global hook to used as the default `easy_hook` on 
+new `Downloader` objects. This supplies a mechanism to set options for the 
+`Downloader` via `Curl.setopt`
+
+It is expected to be function taking two arguments: an `Easy` struct and an 
+`info` NamedTuple with names `url`, `method` and `headers`. 
+"""
 const EASY_HOOK = Ref{Union{Function, Nothing}}(nothing)
 
 """