made body threshold size (the max buffered size after which the response body is buffered to disk) a top-level option

lib/httpx/options.rb

@@ -4,7 +4,8 @@ module HTTPX
   class Options
     MAX_CONCURRENT_REQUESTS = 100
     MAX_RETRIES = 3
-    WINDOW_SIZE = 1 << 14
+    WINDOW_SIZE = 1 << 14 # 16K
+    MAX_BODY_THRESHOLD_SIZE = (1 << 10) * 112 # 112K
 
     class << self
       def inherited(klass)
@@ -48,6 +49,7 @@ module HTTPX
         :max_concurrent_requests  => MAX_CONCURRENT_REQUESTS,
         :max_retries              => MAX_RETRIES,
         :window_size              => WINDOW_SIZE,
+        :body_threshold_size      => MAX_BODY_THRESHOLD_SIZE,
         :request_class            => Class.new(Request),
         :response_class           => Class.new(Response),
         :headers_class            => Class.new(Headers),
@@ -83,6 +85,10 @@ module HTTPX
       self.window_size = Integer(num)
     end
 
+    def_option(:body_threshold_size) do |num|
+      self.body_threshold_size = Integer(num)
+    end
+
     %w[
       params form json body
       proxy follow ssl max_retries

lib/httpx/response.rb

@@ -22,7 +22,7 @@ module HTTPX
       @request = request
       @status = Integer(status)
       @headers = @options.headers_class.new(headers)
-      @body = Body.new(self)
+      @body = Body.new(self, threshold_size: @options.body_threshold_size)
     end 
 
     def <<(data)
@@ -43,9 +43,7 @@ module HTTPX
     end
 
     class Body
-      MAX_THRESHOLD_SIZE = 1024 * (80 + 32) # 112 Kbytes
-  
-      def initialize(response, threshold_size: MAX_THRESHOLD_SIZE)
+      def initialize(response, threshold_size: )
         @response = response
         @headers = response.headers
         @threshold_size = threshold_size

test/options_test.rb

@@ -63,6 +63,7 @@ class OptionsSpec < Minitest::Test
       :body               => nil,
       :follow             => nil,
       :window_size        => 16_384,
+      :body_threshold_size => 114_688,
       :form               => {:bar => "bar"},
       :timeout            => Timeout::PerOperation.new,
       :ssl                => {:foo => "bar"},

test/response_test.rb

@@ -23,7 +23,8 @@ class ResponseTest < Minitest::Test
   end
 
   def test_response_body_to_s
-    body1 = Response::Body.new(Response.new(request, 200, {}))
+    opts = { threshold_size: 1024 }
+    body1 = Response::Body.new(Response.new(request, 200, {}), opts)
     assert body1.empty?, "body must be empty after initialization"
     body1 << "foo"
     assert body1 == "foo", "body must be updated"
@@ -31,14 +32,15 @@ class ResponseTest < Minitest::Test
     body1 << "bar"
     assert body1 == "foobar", "body must buffer subsequent chunks"
 
-    body3 = Response::Body.new(Response.new(request("head"), 200, {}))
+    body3 = Response::Body.new(Response.new(request("head"), 200, {}), opts)
     assert body3.empty?, "body must be empty after initialization"
     assert body3 == "", "HEAD requets body must be empty"
 
   end
 
   def test_response_body_each
-    body1 = Response::Body.new(Response.new(request, 200, {}))
+    opts = { threshold_size: 1024 }
+    body1 = Response::Body.new(Response.new(request, 200, {}), opts)
     body1 << "foo"
     assert body1.each.to_a == %w(foo), "must yield buffer"
     body1 << "foo"