Hi, 

can you please fix it? Thanks so much.
name = 'deltachat_ffi'
operating_system = 'windows'
crate_version = '1.0.0-beta.23'
explanation = '''
Panic occurred in file 'src\liballoc\string.rs' at line 1155
'''
method = 'Panic'
backtrace = '''
stack backtrace:
   0:     0x7ffd1bd6314d - dc_provider_unref
   1:     0x7ffd1bd5fc19 - dc_provider_unref
   2:     0x7ffd1c173fb2 - dc_provider_get_status
   3:     0x7ffd1bcb4f75 - dc_context_new
   4:     0x7ffd1c523eeb - rust_eh_personality
   5:     0x7ffd1c52b0b8 - rust_eh_personality
   6:     0x7ffd1c538fe9 - rust_eh_personality
   7:     0x7ffd1bd7792d - dc_provider_unref
   8:     0x7ffd1bd77dc9 - dc_provider_unref
   9:     0x7ffd1c012f61 - dc_provider_unref
  10:     0x7ffd1c0147a3 - dc_provider_unref
  11:     0x7ffd1c0797ce - dc_provider_unref
  12:     0x7ffd1c0757fc - dc_provider_unref
  13:     0x7ffd1c07fa16 - dc_provider_unref
  14:     0x7ffd1c075550 - dc_provider_unref
  15:     0x7ffd1c06c5ed - dc_provider_unref
  16:     0x7ffd1be3815a - dc_provider_unref
  17:     0x7ffd1bf516e5 - dc_provider_unref
  18:     0x7ffd1c05c79f - dc_provider_unref
  19:     0x7ffd1bcc01d1 - dc_perform_sentbox_fetch
  20:     0x7ffd5e471389 - <unknown>
  21:        0x14221e482 - uv_thread_create
  22:        0x144598150 - uv_stream_set_blocking
  23:     0x7ffd7a327bd4 - BaseThreadInitThunk
  24:     0x7ffd7b1eced1 - RtlUserThreadStart
'''