Function indy_sys::pairwise::indy_set_pairwise_metadata

#[no_mangle]
pub unsafe extern "C" fn indy_set_pairwise_metadata(
    command_handle: Handle, 
    wallet_handle: Handle, 
    their_did: CString, 
    metadata: CString, 
    cb: Option<ResponseEmptyCB>
) -> Error