chore: add conn_buffer_size to swagger and readme

- make the field documented in the api and the readme

Signed-off-by: aerosouund <aerosound161@gmail.com>

Author: aerosouund

CHANGELOG.md

@@ -109,6 +109,12 @@ and this project adheres to
 
 ### Changed
 
+- [#5595](https://github.com/firecracker-microvm/firecracker/pull/5595): Added
+  `vsock_type` field to the vsock device API to denote the type of the
+  underlying socket. Can be `stream` or `seqpacket`
+- [#5595](https://github.com/firecracker-microvm/firecracker/pull/5595): Added
+  `conn_buffer_size` field to denote how many bytes we can internally buffer
+  during receiving large seqpacket packets from the host.
 - [#5564](https://github.com/firecracker-microvm/firecracker/pull/5564): which
   added support for VMClock, uses one extra GSI for the VMClock device itself
   which reduces the available GSIs for VirtIO devices. New maximum values is 92

src/firecracker/swagger/firecracker.yaml

@@ -1865,6 +1865,10 @@ definitions:
           - stream
           - seqpacket
         default: stream
+      conn_buffer_size:
+        type: integer
+        description:
+          The amount in bytes that can be buffered in firecracker during sends.
       vsock_id:
         type: string
         description: