[#270] rewrite Adapters::HttpAdapter to fix missed events in streams

As per:

openownership/register#270 (comment)

Also simplify the code significantly.

lib/register_common/adapters/http_adapter.rb

@@ -8,51 +8,40 @@ module RegisterCommon
   module Adapters
     class HttpAdapter
       HttpError = Class.new(StandardError)
+
       HttpResponse = Struct.new(:status, :headers, :body, :success)
 
-      # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
-      def get(url, params: {}, headers: {}, raise_on_failure: false)
-        streamed = nil
-        response =
-          if block_given?
-            streamed = []
-            current_chunk = ''
-
-            Faraday.new.get(
-              URI(url), params, headers
-            ) do |req|
-              req.options.on_data = proc do |chunk, _overall_received_bytes|
-                current_chunk += chunk
-                lines = current_chunk.split("\n")
-                if current_chunk[-1] == "\n"
-                  lines[0...-1].each do |line|
-                    next if line.empty?
-
-                    yield line
-                  end
-                  current_chunk = ''
-                elsif lines.length > 1
-                  lines[0...-1].each do |line|
-                    next if line.empty?
-
-                    yield line
-                  end
-                  current_chunk = lines[-1]
-                end
-                streamed << chunk
+      def get(url, params: {}, headers: {}, raise_on_failure: false, &block)
+        url = URI(url)
+        res = if block_given?
+                get_streamed(url, params, headers, &block)
+              else
+                get_all(url, params, headers)
               end
-            end
-          else
-            Faraday.new.get(
-              URI(url), params, headers
-            )
-          end
+        raise HttpError if !res.success? && raise_on_failure
+
+        HttpResponse.new(res.status, res.headers, res.body, res.success?)
+      end
 
-        raise HttpError if !response.success? && raise_on_failure
+      private
 
-        HttpResponse.new(response.status, response.headers, streamed ? streamed.join : response.body, response.success?)
+      def get_all(url, params, headers)
+        Faraday.new.get(url, params, headers)
+      end
+
+      def get_streamed(url, params, headers)
+        bfr = ''
+        Faraday.new.get(url, params, headers) do |req|
+          req.options.on_data = proc do |chunk|
+            bfr += chunk
+            lines = bfr.split("\n", -1)
+            lines[0...-1].each do |line|
+              yield line unless line.empty?
+            end
+            bfr = lines[-1]
+          end
+        end
       end
-      # rubocop:enable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
     end
   end
 end