`clippy::non_send_fields_in_send_ty`

Remove the unsafe Send implementation or ensure every field is safe to send between threads.

What it reads

Clippy, with the compiler behind it. The only pass that compiles.

Serious: worth interrupting other work for.

The tier bounds how severe a rule may be; its category bounds the tier.

Turn it off, or make it blocking, without touching the code it flags:

rust-doctor --rule clippy::non_send_fields_in_send_ty=off .
rust-doctor --rule clippy::non_send_fields_in_send_ty=error .