[serialize] move short disconnect to disconnect.rs where it belongs

Signed-off-by: Jurek <[email protected]>

mqtt-format/src/v5/packets/disconnect.rs

@@ -102,10 +102,21 @@ impl<'i> MDisconnect<'i> {
     }
 
     pub fn binary_size(&self) -> u32 {
+        if self.is_short_packet() {
+            return 0;
+        }
         self.reason_code.binary_size() + self.properties.binary_size()
     }
-
+    #[inline]
+    fn is_short_packet(&self) -> bool {
+        // if reason code is NormalDisconnection AND properties are empty, we can skip writing the payload
+        self.reason_code == DisconnectReasonCode::NormalDisconnection
+            && self.properties == DisconnectProperties::new()
+    }
     pub fn write<W: WriteMqttPacket>(&self, buffer: &mut W) -> WResult<W> {
+        if self.is_short_packet() {
+            return Ok(());
+        }
         self.reason_code.write(buffer)?;
         self.properties.write(buffer)
     }

mqtt-format/src/v5/packets/mod.rs

@@ -29,7 +29,6 @@ use super::write::WResult;
 use super::write::WriteMqttPacket;
 use crate::v5::fixed_header::MFixedHeader;
 use crate::v5::packets::connack::MConnack;
-use crate::v5::packets::disconnect::{DisconnectProperties, DisconnectReasonCode};
 use crate::v5::MResult;
 
 pub mod auth;
@@ -163,14 +162,6 @@ impl<'i> MqttPacket<'i> {
                     packet_type: PacketType::Disconnect,
                 };
                 fixed_header.write(buffer)?;
-                // if reason code is NormalDisconnection AND properties are empty, we can skip writing the payload
-                if p.reason_code == DisconnectReasonCode::NormalDisconnection
-                    && p.properties == DisconnectProperties::new()
-                {
-                    // writing length of packet 0
-                    crate::v5::integers::write_variable_u32(buffer, 0)?;
-                    return Ok(());
-                }
                 crate::v5::integers::write_variable_u32(buffer, p.binary_size())?;
                 p.write(buffer)?;
             }