added limited buffer type; it's a weak buffer, in that it doesn't break if buffer limit it is exceeded, it just doesn't let append more data after limit is reached

lib/httpx/buffer.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "forwardable"
+
+module HTTPX
+  class Buffer
+    extend Forwardable
+
+    def_delegator :@buffer, :<<
+
+    def_delegator :@buffer, :to_s
+    
+    def_delegator :@buffer, :to_str
+    
+    def_delegator :@buffer, :empty?
+    
+    def_delegator :@buffer, :slice!
+
+    def initialize(limit)
+      @buffer = "".b
+      @limit = limit
+    end
+
+    def <<(data)
+      @buffer << data
+    end
+
+    def full?
+      @buffer.bytesize >= @limit
+    end
+  end
+end

lib/httpx/channel.rb

@@ -1,12 +1,15 @@
 # frozen_string_literal: true
 
 require "httpx/io"
+require "httpx/buffer"
 
 module HTTPX
   class Channel
     require "httpx/channel/http2"
     require "httpx/channel/http1"
 
+    BUFFER_SIZE = 1 << 14
+
     PROTOCOLS = {
       "h2"       => HTTP2,
       "http/1.1" => HTTP1
@@ -30,8 +33,8 @@ module HTTPX
       @io = io
       @options = Options.new(options)
       @window_size = @options.window_size
-      @read_buffer = +""
-      @write_buffer = +""
+      @read_buffer = "".b
+      @write_buffer = Buffer.new(BUFFER_SIZE)
       @pending = []
       @on_response = on_response
     end