Panic when piping to less and ctrl-c'ing out about pkghist HOT 1 CLOSED

stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:47
   3: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:36
   4: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:200
   5: std::panicking::default_hook
             at src/libstd/panicking.rs:214
   6: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:477
   7: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:384
   8: std::panicking::begin_panic_fmt
             at src/libstd/panicking.rs:339
   9: std::io::stdio::print_to
             at src/libstd/io/stdio.rs:792
  10: std::io::stdio::_print
             at src/libstd/io/stdio.rs:802
  11: pkghist::pkghist::format_plain
             at src/pkghist.rs:109
  12: <pkghist::opt::Format as pkghist::pkghist::Printer>::print
             at src/pkghist.rs:134
  13: pkghist::pkghist::run
             at src/pkghist.rs:47
  14: pkghist::main
             at src/main.rs:14
  15: std::rt::lang_start::{{closure}}
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/rt.rs:64
  16: std::rt::lang_start_internal::{{closure}}
             at src/libstd/rt.rs:49
  17: std::panicking::try::do_call
             at src/libstd/panicking.rs:296
  18: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:82
  19: std::panicking::try
             at src/libstd/panicking.rs:275
  20: std::panic::catch_unwind
             at src/libstd/panic.rs:394
  21: std::rt::lang_start_internal
             at src/libstd/rt.rs:48
  22: std::rt::lang_start
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/rt.rs:64
  23: main
  24: __libc_start_main
  25: _start