refactor: Remove unnecessary bytes() conversions for Buffer comparisons

Eliminate 3 redundant bytes() conversions where memoryview comparison
works directly:
- BGP marker check: memoryview slice compares correctly with bytes
- NextHop empty check: truthiness works for both bytes and memoryview

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: thomas-mangin

src/exabgp/bgp/message/update/attribute/nexthop.py

@@ -129,7 +129,7 @@ def pack_attribute(self, negotiated: Negotiated) -> bytes:
 
     @classmethod
     def unpack_attribute(cls, data: Buffer, negotiated: Negotiated) -> 'NextHop | IP':
-        if not bytes(data):
+        if not data:
             return IP.NoNextHop
         return cls.from_packet(data)
 

src/exabgp/reactor/network/connection.py

@@ -384,7 +384,7 @@ def reader(self) -> Iterator[tuple[int, int, Buffer, Buffer, NotifyError | None]
             if not header:
                 yield 0, 0, memoryview(b''), memoryview(b''), None
 
-        if not bytes(header[:16]) == Message.MARKER:
+        if header[:16] != Message.MARKER:
             report = 'The packet received does not contain a BGP marker'
             yield 0, 0, header, memoryview(b''), NotifyError(1, 1, report)
             return
@@ -428,7 +428,7 @@ async def reader_async(self) -> tuple[int, int, Buffer, Buffer, NotifyError | No
         # Read BGP header (19 bytes)
         header = await self._reader_async(Message.HEADER_LEN)
 
-        if not bytes(header[:16]) == Message.MARKER:
+        if header[:16] != Message.MARKER:
             report = 'The packet received does not contain a BGP marker'
             return 0, 0, header, memoryview(b''), NotifyError(1, 1, report)