Emits a http_request_done internal notification.

With networking enabled, CDP listens to this event and emits a
`Network.loadingFinished` event. This is event is used by puppeteer to know that
details about the response (i.e. the body) can be queries.

Added dummy handling for the Network.getResponseBody message. Returns an
empty body. Needed because we emit the loadingFinished event which signals
to drivers that they can ask for the body.

src/http/Client.zig

@@ -376,8 +376,14 @@ fn perform(self: *Client, timeout_ms: c_int) !void {
                 // transfer isn't valid at this point, don't use it.
                 log.err(.http, "done_callback", .{ .err = err });
                 self.requestFailed(transfer, err);
+                continue;
             };
-            // self.requestComplete(transfer);
+
+            if (transfer.client.notification) |notification| {
+                notification.dispatch(.http_request_done, &.{
+                    .transfer = transfer,
+                });
+            }
         } else |err| {
             self.requestFailed(transfer, err);
         }
@@ -552,11 +558,15 @@ pub const Transfer = struct {
     uri: std.Uri, // used for setting/getting the cookie
     ctx: *anyopaque, // copied from req.ctx to make it easier for callback handlers
     client: *Client,
-    _notified_fail: bool = false,
+    // total bytes received in the response, including the response status line,
+    // the headers, and the [encoded] body.
+    bytes_received: usize = 0,
 
     // We'll store the response header here
     response_header: ?ResponseHeader = null,
 
+    _notified_fail: bool = false,
+
     _handle: ?*Handle = null,
 
     _redirecting: bool = false,
@@ -716,9 +726,11 @@ pub const Transfer = struct {
                 .url = url,
                 .status = status,
             };
+            transfer.bytes_received = buf_len;
             return buf_len;
         }
 
+        transfer.bytes_received += buf_len;
         if (buf_len == 2) {
             if (getResponseHeader(easy, "content-type", 0)) |ct| {
                 var hdr = &transfer.response_header.?;
@@ -777,6 +789,7 @@ pub const Transfer = struct {
             return chunk_len;
         }
 
+        transfer.bytes_received += chunk_len;
         transfer.req.data_callback(transfer, buffer[0..chunk_len]) catch |err| {
             log.err(.http, "data_callback", .{ .err = err, .req = transfer });
             return c.CURL_WRITEFUNC_ERROR;