The replay subsystem does not provide any way to see what's going on
and how the replay events interleave with other things happening in QEMU.
Add trace events to improve debuggability; to avoid having too many
events reimplement all functions in terms of (non-traced) replay_getc
and replay_putc and add a single trace event for each datum that is
extracted or written.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
