diff --git a/examples/asio-sv2.cc b/examples/asio-sv2.cc
index 2fba5bbf..63eb1800 100644
--- a/examples/asio-sv2.cc
+++ b/examples/asio-sv2.cc
@@ -96,7 +96,7 @@ int main(int argc, char *argv[]) {
                        header_value{http_date(stbuf.st_mtime)});
       }
       res.write_head(200, std::move(header));
-      res.end(file_reader_from_fd(fd));
+      res.end(file_generator_from_fd(fd));
     });
 
     server.listen("*", port);
diff --git a/src/asio_client_request_impl.cc b/src/asio_client_request_impl.cc
index 4975cefd..584a1396 100644
--- a/src/asio_client_request_impl.cc
+++ b/src/asio_client_request_impl.cc
@@ -63,12 +63,13 @@ void request_impl::call_on_close(uint32_t error_code) {
   }
 }
 
-void request_impl::on_read(read_cb cb) { read_cb_ = std::move(cb); }
+void request_impl::on_read(generator_cb cb) { generator_cb_ = std::move(cb); }
 
-read_cb::result_type request_impl::call_on_read(uint8_t *buf, std::size_t len,
-                                                uint32_t *data_flags) {
-  if (read_cb_) {
-    return read_cb_(buf, len, data_flags);
+generator_cb::result_type request_impl::call_on_read(uint8_t *buf,
+                                                     std::size_t len,
+                                                     uint32_t *data_flags) {
+  if (generator_cb_) {
+    return generator_cb_(buf, len, data_flags);
   }
 
   *data_flags |= NGHTTP2_DATA_FLAG_EOF;
diff --git a/src/asio_client_request_impl.h b/src/asio_client_request_impl.h
index bd6b1541..f5d5249b 100644
--- a/src/asio_client_request_impl.h
+++ b/src/asio_client_request_impl.h
@@ -54,9 +54,9 @@ public:
   void on_close(close_cb cb);
   void call_on_close(uint32_t error_code);
 
-  void on_read(read_cb cb);
-  read_cb::result_type call_on_read(uint8_t *buf, std::size_t len,
-                                    uint32_t *data_flags);
+  void on_read(generator_cb cb);
+  generator_cb::result_type call_on_read(uint8_t *buf, std::size_t len,
+                                         uint32_t *data_flags);
 
   void resume();
 
@@ -78,7 +78,7 @@ private:
   response_cb response_cb_;
   request_cb push_request_cb_;
   close_cb close_cb_;
-  read_cb read_cb_;
+  generator_cb generator_cb_;
   class stream *strm_;
   uri_ref uri_;
   std::string method_;
diff --git a/src/asio_client_session.cc b/src/asio_client_session.cc
index 8c002e21..2e03f51e 100644
--- a/src/asio_client_session.cc
+++ b/src/asio_client_session.cc
@@ -64,20 +64,20 @@ boost::asio::io_service &session::io_service() const {
 const request *session::submit(boost::system::error_code &ec,
                                const std::string &method,
                                const std::string &uri, header_map h) const {
-  return impl_->submit(ec, method, uri, read_cb(), std::move(h));
+  return impl_->submit(ec, method, uri, generator_cb(), std::move(h));
 }
 
 const request *session::submit(boost::system::error_code &ec,
                                const std::string &method,
                                const std::string &uri, std::string data,
                                header_map h) const {
-  return impl_->submit(ec, method, uri, string_reader(std::move(data)),
+  return impl_->submit(ec, method, uri, string_generator(std::move(data)),
                        std::move(h));
 }
 
 const request *session::submit(boost::system::error_code &ec,
                                const std::string &method,
-                               const std::string &uri, read_cb cb,
+                               const std::string &uri, generator_cb cb,
                                header_map h) const {
   return impl_->submit(ec, method, uri, std::move(cb), std::move(h));
 }
diff --git a/src/asio_client_session_impl.cc b/src/asio_client_session_impl.cc
index ec976f97..c85be305 100644
--- a/src/asio_client_session_impl.cc
+++ b/src/asio_client_session_impl.cc
@@ -364,7 +364,7 @@ std::unique_ptr<stream> session_impl::create_stream() {
 
 const request *session_impl::submit(boost::system::error_code &ec,
                                     const std::string &method,
-                                    const std::string &uri, read_cb cb,
+                                    const std::string &uri, generator_cb cb,
                                     header_map h) {
   ec.clear();
 
diff --git a/src/asio_client_session_impl.h b/src/asio_client_session_impl.h
index 045131aa..1cecedeb 100644
--- a/src/asio_client_session_impl.h
+++ b/src/asio_client_session_impl.h
@@ -63,7 +63,7 @@ public:
 
   const request *submit(boost::system::error_code &ec,
                         const std::string &method, const std::string &uri,
-                        read_cb cb, header_map h);
+                        generator_cb cb, header_map h);
 
   virtual void start_connect(tcp::resolver::iterator endpoint_it) = 0;
   virtual tcp::socket &socket() = 0;
diff --git a/src/asio_common.cc b/src/asio_common.cc
index 3fec23e9..3025c493 100644
--- a/src/asio_common.cc
+++ b/src/asio_common.cc
@@ -47,7 +47,7 @@ boost::system::error_code make_error_code(nghttp2_error ev) {
   return boost::system::error_code(static_cast<int>(ev), nghttp2_category());
 }
 
-read_cb string_reader(std::string data) {
+generator_cb string_generator(std::string data) {
   auto strio = std::make_shared<std::pair<std::string, size_t>>(std::move(data),
                                                                 data.size());
   return [strio](uint8_t *buf, size_t len, uint32_t *data_flags) {
@@ -63,7 +63,7 @@ read_cb string_reader(std::string data) {
   };
 }
 
-read_cb deferred_reader() {
+generator_cb deferred_generator() {
   return [](uint8_t *buf, size_t len,
             uint32_t *data_flags) { return NGHTTP2_ERR_DEFERRED; };
 }
@@ -74,20 +74,20 @@ std::shared_ptr<Defer<F, T...>> defer_shared(F &&f, T &&... t) {
                                           std::forward<T>(t)...);
 }
 
-read_cb file_reader(const std::string &path) {
+generator_cb file_generator(const std::string &path) {
   auto fd = open(path.c_str(), O_RDONLY);
   if (fd == -1) {
-    return read_cb();
+    return generator_cb();
   }
 
-  return file_reader_from_fd(fd);
+  return file_generator_from_fd(fd);
 }
 
-read_cb file_reader_from_fd(int fd) {
+generator_cb file_generator_from_fd(int fd) {
   auto d = defer_shared(close, fd);
 
   return [fd, d](uint8_t *buf, size_t len, uint32_t *data_flags)
-      -> read_cb::result_type {
+      -> generator_cb::result_type {
     ssize_t n;
     while ((n = read(fd, buf, len)) == -1 && errno == EINTR)
       ;
diff --git a/src/asio_common.h b/src/asio_common.h
index 28a69a31..8f59a0d1 100644
--- a/src/asio_common.h
+++ b/src/asio_common.h
@@ -39,10 +39,10 @@ namespace asio_http2 {
 
 boost::system::error_code make_error_code(nghttp2_error ev);
 
-read_cb string_reader(std::string data);
+generator_cb string_generator(std::string data);
 
-// Returns read_cb, which just returns NGHTTP2_ERR_DEFERRED
-read_cb deferred_reader();
+// Returns generator_cb, which just returns NGHTTP2_ERR_DEFERRED
+generator_cb deferred_generator();
 
 template <typename InputIt>
 void split_path(uri_ref &dst, InputIt first, InputIt last) {
diff --git a/src/asio_server_response.cc b/src/asio_server_response.cc
index 3cb074de..6952b586 100644
--- a/src/asio_server_response.cc
+++ b/src/asio_server_response.cc
@@ -44,7 +44,7 @@ void response::write_head(unsigned int status_code, header_map h) const {
 
 void response::end(std::string data) const { impl_->end(std::move(data)); }
 
-void response::end(read_cb cb) const { impl_->end(std::move(cb)); }
+void response::end(generator_cb cb) const { impl_->end(std::move(cb)); }
 
 void response::on_close(close_cb cb) const { impl_->on_close(std::move(cb)); }
 
diff --git a/src/asio_server_response_impl.cc b/src/asio_server_response_impl.cc
index 205cac19..5661e610 100644
--- a/src/asio_server_response_impl.cc
+++ b/src/asio_server_response_impl.cc
@@ -33,7 +33,7 @@ namespace asio_http2 {
 namespace server {
 
 response_impl::response_impl()
-    : strm_(nullptr), read_cb_(deferred_reader()), status_code_(200),
+    : strm_(nullptr), generator_cb_(deferred_generator()), status_code_(200),
       state_(response_state::INITIAL), pushed_(false),
       push_promise_sent_(false) {}
 
@@ -57,20 +57,20 @@ void response_impl::write_head(unsigned int status_code, header_map h) {
 }
 
 void response_impl::end(std::string data) {
-  end(string_reader(std::move(data)));
+  end(string_generator(std::move(data)));
 }
 
-void response_impl::end(read_cb cb) {
+void response_impl::end(generator_cb cb) {
   if (state_ == response_state::BODY_STARTED) {
     return;
   }
 
-  read_cb_ = std::move(cb);
+  generator_cb_ = std::move(cb);
 
   if (state_ == response_state::INITIAL) {
     write_head(status_code_);
   } else {
-    // read_cb is changed, start writing in case it is deferred.
+    // generator_cb is changed, start writing in case it is deferred.
     auto handler = strm_->handler();
     handler->resume(*strm_);
   }
@@ -133,10 +133,10 @@ const header_map &response_impl::header() const { return header_; }
 
 void response_impl::stream(class stream *s) { strm_ = s; }
 
-read_cb::result_type response_impl::call_read(uint8_t *data, std::size_t len,
-                                              uint32_t *data_flags) {
-  if (read_cb_) {
-    return read_cb_(data, len, data_flags);
+generator_cb::result_type
+response_impl::call_read(uint8_t *data, std::size_t len, uint32_t *data_flags) {
+  if (generator_cb_) {
+    return generator_cb_(data, len, data_flags);
   }
 
   *data_flags |= NGHTTP2_DATA_FLAG_EOF;
diff --git a/src/asio_server_response_impl.h b/src/asio_server_response_impl.h
index fb3e3172..c85101a0 100644
--- a/src/asio_server_response_impl.h
+++ b/src/asio_server_response_impl.h
@@ -48,7 +48,7 @@ public:
   response_impl();
   void write_head(unsigned int status_code, header_map h = {});
   void end(std::string data = "");
-  void end(read_cb cb);
+  void end(generator_cb cb);
   void on_close(close_cb cb);
   void resume();
 
@@ -66,14 +66,14 @@ public:
   void pushed(bool f);
   void push_promise_sent();
   void stream(class stream *s);
-  read_cb::result_type call_read(uint8_t *data, std::size_t len,
-                                 uint32_t *data_flags);
+  generator_cb::result_type call_read(uint8_t *data, std::size_t len,
+                                      uint32_t *data_flags);
   void call_on_close(uint32_t error_code);
 
 private:
   class stream *strm_;
   header_map header_;
-  read_cb read_cb_;
+  generator_cb generator_cb_;
   close_cb close_cb_;
   unsigned int status_code_;
   response_state state_;
diff --git a/src/includes/nghttp2/asio_http2.h b/src/includes/nghttp2/asio_http2.h
index 635bb65f..670952f1 100644
--- a/src/includes/nghttp2/asio_http2.h
+++ b/src/includes/nghttp2/asio_http2.h
@@ -100,16 +100,16 @@ typedef std::function<void(uint32_t)> close_cb;
 // of the error and request/response must be closed, return
 // NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE.
 typedef std::function<
-    ssize_t(uint8_t *buf, std::size_t len, uint32_t *data_flags)> read_cb;
+    ssize_t(uint8_t *buf, std::size_t len, uint32_t *data_flags)> generator_cb;
 
 // Convenient function to create function to read file denoted by
 // |path|.  This can be passed to response::end().
-read_cb file_reader(const std::string &path);
+generator_cb file_generator(const std::string &path);
 
-// Like file_reader(const std::string&), but it takes opened file
+// Like file_generator(const std::string&), but it takes opened file
 // descriptor.  The passed descriptor will be closed when returned
 // function object is destroyed.
-read_cb file_reader_from_fd(int fd);
+generator_cb file_generator_from_fd(int fd);
 
 // Validates path so that it does not contain directory traversal
 // vector.  Returns true if path is safe.  The |path| must start with
diff --git a/src/includes/nghttp2/asio_http2_client.h b/src/includes/nghttp2/asio_http2_client.h
index 76ef8c91..9d4750d3 100644
--- a/src/includes/nghttp2/asio_http2_client.h
+++ b/src/includes/nghttp2/asio_http2_client.h
@@ -165,7 +165,7 @@ public:
   // nullptr and |ec| contains error message.
   const request *submit(boost::system::error_code &ec,
                         const std::string &method, const std::string &uri,
-                        read_cb cb, header_map h = {}) const;
+                        generator_cb cb, header_map h = {}) const;
 
 private:
   std::unique_ptr<session_impl> impl_;
diff --git a/src/includes/nghttp2/asio_http2_server.h b/src/includes/nghttp2/asio_http2_server.h
index 23649740..a3df3310 100644
--- a/src/includes/nghttp2/asio_http2_server.h
+++ b/src/includes/nghttp2/asio_http2_server.h
@@ -79,7 +79,7 @@ public:
 
   // Sets callback as a generator of the response body.  No further
   // call of end() is allowed.
-  void end(read_cb cb) const;
+  void end(generator_cb cb) const;
 
   // Sets callback which is invoked when this request and response are
   // finished.  After the invocation of this callback, the application