diff --git a/libp2p/security/base_session.py b/libp2p/security/base_session.py
index a7df0e9..899cc0e 100644
--- a/libp2p/security/base_session.py
+++ b/libp2p/security/base_session.py
@@ -1,7 +1,7 @@
 from typing import Optional
 
 from libp2p.crypto.keys import PrivateKey, PublicKey
-from libp2p.network.connection.raw_connection_interface import IRawConnection
+from libp2p.io.msgio import MsgIOReadWriter
 from libp2p.peer.id import ID
 from libp2p.security.secure_conn_interface import ISecureConn
 
@@ -14,7 +14,7 @@ class BaseSession(ISecureConn):
 
     local_peer: ID
     local_private_key: PrivateKey
-    conn: IRawConnection
+    conn: MsgIOReadWriter
     remote_peer_id: ID
     remote_permanent_pubkey: PublicKey
 
@@ -22,7 +22,7 @@ class BaseSession(ISecureConn):
         self,
         local_peer: ID,
         local_private_key: PrivateKey,
-        conn: IRawConnection,
+        conn: MsgIOReadWriter,
         peer_id: Optional[ID] = None,
     ) -> None:
         self.local_peer = local_peer
@@ -33,8 +33,9 @@ class BaseSession(ISecureConn):
         self.conn = conn
         self.initiator = peer_id is not None
 
-    async def write(self, data: bytes) -> None:
+    async def write(self, data: bytes) -> int:
         await self.conn.write(data)
+        return len(data)
 
     async def read(self, n: int = -1) -> bytes:
         return await self.conn.read(n)
diff --git a/libp2p/security/insecure/transport.py b/libp2p/security/insecure/transport.py
index 8ad2e61..3cb094e 100644
--- a/libp2p/security/insecure/transport.py
+++ b/libp2p/security/insecure/transport.py
@@ -1,6 +1,7 @@
 from libp2p.crypto.keys import PublicKey
 from libp2p.crypto.pb import crypto_pb2
 from libp2p.crypto.utils import pubkey_from_protobuf
+from libp2p.io.msgio import MsgIOReadWriter
 from libp2p.network.connection.raw_connection_interface import IRawConnection
 from libp2p.peer.id import ID
 from libp2p.security.base_session import BaseSession
@@ -76,7 +77,8 @@ class InsecureTransport(BaseSecureTransport):
         for an inbound connection (i.e. we are not the initiator)
         :return: secure connection object (that implements secure_conn_interface)
         """
-        session = InsecureSession(self.local_peer, self.local_private_key, conn)
+        msg_io = MsgIOReadWriter(conn)
+        session = InsecureSession(self.local_peer, self.local_private_key, msg_io)
         await session.run_handshake()
         return session
 
@@ -86,8 +88,9 @@ class InsecureTransport(BaseSecureTransport):
         for an inbound connection (i.e. we are the initiator)
         :return: secure connection object (that implements secure_conn_interface)
         """
+        msg_io = MsgIOReadWriter(conn)
         session = InsecureSession(
-            self.local_peer, self.local_private_key, conn, peer_id
+            self.local_peer, self.local_private_key, msg_io, peer_id
         )
         await session.run_handshake()
         return session
diff --git a/libp2p/utils.py b/libp2p/utils.py
index a309064..e1c45fd 100644
--- a/libp2p/utils.py
+++ b/libp2p/utils.py
@@ -2,6 +2,7 @@ import itertools
 import math
 
 from libp2p.exceptions import ParseError
+from libp2p.io.abc import Reader
 from libp2p.typing import StreamReader
 
 # Unsigned LEB128(varint codec)
@@ -98,7 +99,7 @@ def encode_fixedint_prefixed(msg_bytes: bytes) -> bytes:
     return len_prefix + msg_bytes
 
 
-async def read_fixedint_prefixed(reader: StreamReader) -> bytes:
+async def read_fixedint_prefixed(reader: Reader) -> bytes:
     len_bytes = await reader.read(SIZE_LEN_BYTES)
     len_int = int.from_bytes(len_bytes, "big")
     return await reader.read(len_int)