RUBY_UBF_IO       104 ext/socket/socket.c #define BLOCKING_REGION(func, arg) (long)rb_thread_blocking_region((func), (arg), RUBY_UBF_IO, 0)
RUBY_UBF_IO      3482 file.c             while ((int)rb_thread_blocking_region(rb_thread_flock, op, RUBY_UBF_IO, 0) < 0) {
RUBY_UBF_IO       525 io.c               return rb_thread_blocking_region(internal_read_func, &iis, RUBY_UBF_IO, 0);
RUBY_UBF_IO       536 io.c               return rb_thread_blocking_region(internal_write_func, &iis, RUBY_UBF_IO, 0);
RUBY_UBF_IO      4157 io.c               return (int)rb_thread_blocking_region(sysopen_func, &data, RUBY_UBF_IO, 0);
RUBY_UBF_IO      7778 io.c               return rb_thread_blocking_region(nogvl_copy_stream_func, (void*)stp, RUBY_UBF_IO, 0);
RUBY_UBF_IO      1040 thread.c           if (ubf == RUBY_UBF_IO || ubf == RUBY_UBF_PROCESS) {