diff --git a/Cargo.toml b/Cargo.toml
index de03638..0ad6b91 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,7 @@ slab = "0.4.0"
 string = { git = "https://github.com/carllerche/string" }
 
 [dev-dependencies]
-mock-io = { git = "https://github.com/carllerche/mock-io" }
+mock-io = { git = "https://github.com/carllerche/mock-io", branch = "experiments" }
 
 # Fuzzing
 quickcheck = "0.4.1"
diff --git a/src/proto/settings.rs b/src/proto/settings.rs
index 31ee017..69683fd 100644
--- a/src/proto/settings.rs
+++ b/src/proto/settings.rs
@@ -38,9 +38,12 @@ impl Settings {
             let frame = frame::Settings::ack();
 
             if let AsyncSink::NotReady(_) = dst.start_send(frame.into())? {
+                trace!("failed to send ACK");
                 return Ok(Async::NotReady);
             }
 
+            trace!("ACK sent");
+
             dst.apply_remote_settings(settings);
             streams.apply_remote_settings(settings);
         }
diff --git a/tests/prioritization.rs b/tests/prioritization.rs
index 070903e..b561bf5 100644
--- a/tests/prioritization.rs
+++ b/tests/prioritization.rs
@@ -45,7 +45,7 @@ fn single_stream_send_large_body() {
 }
 
 #[test]
-fn single_stream_send_extra_large_body_multi_frames() {
+fn single_stream_send_extra_large_body_multi_frames_one_buffer() {
     let _ = ::env_logger::init();
 
     let payload = vec![0; 32_768];
@@ -91,3 +91,64 @@ fn single_stream_send_extra_large_body_multi_frames() {
 
     h2.wait().unwrap();
 }
+
+#[test]
+fn single_stream_send_extra_large_body_multi_frames_multi_buffer() {
+    let _ = ::env_logger::init();
+
+    let payload = vec![0; 32_768];
+
+    let mock = mock_io::Builder::new()
+        // .handshake()
+        .write(b"PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n")
+        .write(frames::SETTINGS)
+        .read(frames::SETTINGS)
+        // Add wait to force the data writes to chill
+        .wait(Duration::from_millis(10))
+
+        // Rest
+
+        .write(&[
+            // POST /
+            0, 0, 16, 1, 4, 0, 0, 0, 1, 131, 135, 65, 139, 157, 41,
+            172, 75, 143, 168, 233, 25, 151, 33, 233, 132,
+        ])
+        .write(&[
+            // DATA
+            0, 64, 0, 0, 0, 0, 0, 0, 1,
+        ])
+        .write(&payload[0..16_384])
+
+        .write(frames::SETTINGS_ACK)
+        .read(frames::SETTINGS_ACK)
+        .wait(Duration::from_millis(10))
+
+        .write(&[
+            // DATA
+            0, 64, 0, 0, 1, 0, 0, 0, 1,
+        ])
+        .write(&payload[16_384..])
+        // Read response
+        .read(&[0, 0, 1, 1, 5, 0, 0, 0, 1, 0x89])
+        .build();
+
+    let mut h2 = Client::handshake(mock)
+        .wait().unwrap();
+
+    let request = Request::builder()
+        .method(method::POST)
+        .uri("https://http2.akamai.com/")
+        .body(()).unwrap();
+
+    let mut stream = h2.request(request, false).unwrap();
+
+    // Send the data
+    stream.send_data(payload.into(), true).unwrap();
+
+    // Get the response
+    let resp = h2.run(poll_fn(|| stream.poll_response())).unwrap();
+
+    assert_eq!(resp.status(), status::NO_CONTENT);
+
+    h2.wait().unwrap();
+}
diff --git a/tests/support/mod.rs b/tests/support/mod.rs
index 47869d8..8f58b44 100644
--- a/tests/support/mod.rs
+++ b/tests/support/mod.rs
@@ -35,6 +35,8 @@ pub use self::bytes::{
     IntoBuf,
 };
 
+pub use std::time::Duration;
+
 use tokio_io::{AsyncRead, AsyncWrite};
 
 pub trait MockH2 {