librust-gperftools-dev is declared Multi-Arch: same, but fails to
coinstall.

The file /usr/share/cargo/registry/gperftools-0.2.0/my-profile.prof is
shared by librust-gperftools-dev version 0.2.0-1+b2 as present in
trixie|forky|unstable with varying content.

Please ensure that shared files have bit-identical content across
architectures, move architecture-dependent files to
architecture-dependent paths or remove the Multi-Arch: same field.

Kind regards

Helmut Grohne