diff --git a/picotls/picotls.nim b/picotls/picotls.nim
index fc45c8b..d322c29 100644
--- a/picotls/picotls.nim
+++ b/picotls/picotls.nim
@@ -60,7 +60,7 @@ type
   VerifySignCb* = proc(verify_ctx: pointer, data: ptls_iovec_t,
                        sign: ptls_iovec_t): cint {.cdecl.}
 
-  ptls_t* {.importc, header: "picotls.h", bycopy.} = object
+  ptls_t* {.importc, header: "picotls.h", incompleteStruct.} = object
 
   ptls_key_exchange_algorithm_t* {.importc, header: "picotls.h", bycopy.} = object
     id*: uint16
@@ -282,3 +282,6 @@ proc ptls_iovec_init*(p: pointer, len: csize_t): ptls_iovec_t {.importc, header:
 
 proc ptls_load_certificates*(ctx: ptr ptls_context_t, cert_pem_file: cstring):
                             cint {.importc, header: "picotls.h", cdecl.}
+
+proc ptls_get_data_ptr*(tls: ptr ptls_t): ptr pointer
+                       {.importc, header: "picotls.h", cdecl.}
diff --git a/quicly/quicly.nim b/quicly/quicly.nim
index 5fbffa1..c3ec86c 100644
--- a/quicly/quicly.nim
+++ b/quicly/quicly.nim
@@ -16,6 +16,7 @@ from constants import
   quicly_stream_t
 
 from ../picotls/picotls import
+  ptls_t,
   ptls_aead_algorithm_t,
   ptls_aead_context_t,
   ptls_buffer_t,
@@ -249,3 +250,6 @@ proc quicly_get_socklen*(sa: ptr SockAddr | ptr Sockaddr_storage): SockLen
 
 proc quicly_get_first_timeout*(conn: ptr quicly_conn_t): int64
                               {.importc, header: "quicly.h", cdecl.}
+
+proc quicly_get_data*(conn: ptr quicly_conn_t): ptr pointer
+                     {.importc, header: "quicly.h", cdecl.}