Everywhere: Remove unintentional partial stream reads and writes

Author: https://github.com/timschumi
Commit: ae51c1821c
Pull-request: https://github.com/SerenityOS/serenity/pull/17684
Reviewed-by: https://github.com/JanDeVisser ✅
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/linusg ✅

Userland/Services/EchoServer/Client.cpp

@@ -40,8 +40,7 @@ ErrorOr<void> Client::drain_socket()
             break;
         }
 
-        // FIXME: This should write the entire span.
-        TRY(m_socket->write_some(bytes_read));
+        TRY(m_socket->write_until_depleted(bytes_read));
     }
 
     return {};