quic.SessionOptions.preferredAddressPolicy

When the remote peer advertises a preferred address, this option specifies whether to use it or ignore it. The default is 'ignore' because honoring a server's preferred address causes the client to migrate its connection to a different IP address, which can be exploited for data exfiltration attacks that are indistinguishable from legitimate QUIC connection migration at the network level. Set to 'use' only when connecting to trusted servers that require preferred address migration.