AK/ByteBuffer+Everywhere: Handle errors in ByteBuffer::slice()

Author: https://github.com/mjz19910
Commit: c10d48b72c
Pull-request: https://github.com/SerenityOS/serenity/pull/14268
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibTLS/TLSv12.cpp

@@ -92,7 +92,8 @@ void TLSv12::consume(ReadonlyBytes record)
     }
 
     if (index) {
-        m_context.message_buffer = m_context.message_buffer.slice(index, m_context.message_buffer.size() - index);
+        // FIXME: Propagate errors.
+        m_context.message_buffer = MUST(m_context.message_buffer.slice(index, m_context.message_buffer.size() - index));
     }
 }