added draft logic comments for fetchers implementation

lib/crawly/worker.ex

@@ -43,16 +43,18 @@ defmodule Crawly.Worker do
           case :epipe.run(functions, {request, spider_name}) do
             {:error, _step, reason, _step_state} ->
               # TODO: Add retry logic
-              Logger.error(
-                fn ->
-                  "Crawly worker could not process the request to #{inspect(request.url)}
+              Logger.error(fn ->
+                "Crawly worker could not process the request to #{
+                  inspect(request.url)
+                }
                   reason: #{inspect(reason)}"
-                end)
+              end)
+
               @default_backoff
+
             {:ok, _result} ->
               @default_backoff
           end
-
       end
 
     Process.send_after(self(), :work, new_backoff)
@@ -66,6 +68,9 @@ defmodule Crawly.Worker do
              response: HTTPoison.Response.t(),
              result: {:ok, response, spider_name} | {:error, term()}
   defp get_response({request, spider_name}) do
+    # check if spider-level fetcher is set. Overrides the globally configured fetcher.
+    # if not set, log warning for explicit config preferred, get the globally-configured fetcher. Defaults to HTTPoison
+
     case HTTPoison.get(request.url, request.headers, request.options) do
       {:ok, response} ->
         {:ok, {response, spider_name}}