pub unsafe extern "C" fn switch_event_add_presence_data_cols(
channel: *mut switch_channel_t,
event: *mut switch_event_t,
prefix: *const c_char,
)pub unsafe extern "C" fn switch_event_add_presence_data_cols(
channel: *mut switch_channel_t,
event: *mut switch_event_t,
prefix: *const c_char,
)