pub unsafe extern "C" fn mdbx_estimate_range( txn: *mut MDBX_txn, dbi: MDBX_dbi, begin_key: *mut MDBX_val, begin_data: *mut MDBX_val, end_key: *mut MDBX_val, end_data: *mut MDBX_val, distance_items: *mut isize) -> c_int