ios - How to use PHAssetResourceRequestOptions progressHandler/PHAssetResourceProgressHandler -

i'm trying retrieve/download video/frames of live photo. api documents there possible scenario live photos store @ icloud. in order retrieve them need declare

let options = phassetresourcerequestoptions()         options.networkaccessallowed = true   

i'm trying create progress bar while live photo being download. according api, need declare properties:

public var progresshandler: phassetresourceprogresshandler?  progress     floating-point value indicating progress of download.  value of 0.0 indicates download has started, , value of 1.0 indicates download complete.  

i haven't found correct way retrieve yet. suggestion?

full code :

 let assestresource = phassetresource.assetresourcesforasset(asset)  let options = phassetresourcerequestoptions()  options.networkaccessallowed = true assetres in assestresource {             print(assetres.type.rawvalue)             if (assetres.type == .pairedvideo) {                 print("imagetaken")                 manager.writedataforassetresource(assetres, tofile: documentsurl,    options: options, completionhandler: { (error) -> void in                     if error == nil                     {                      }                     else                     {                         print(error)                     }                 }) 

yes, unfortunately, there apple bug icloud downloads + phassetresourcemanager. following error regardless of asset type:

error: missing resource download context

instead, use phimagemanager. need have unique request each type of phasset:

- (void)downloadasset:(phasset *)asset tourl:(nsurl *)url completion:(void (^)(void))completion {     if (asset.mediatype == phassetmediatypeimage && (asset.mediasubtypes & phassetmediasubtypephotolive))     {         phlivephotorequestoptions *options = [phlivephotorequestoptions new];         options.networkaccessallowed = yes;         [[phimagemanager defaultmanager] requestlivephotoforasset:asset targetsize:cgsizezero contentmode:phimagecontentmodeaspectfill options:options resulthandler:^(phlivephoto * _nullable livephoto, nsdictionary * _nullable info) {             if ([info objectforkey:phimageerrorkey] == nil)             {                 nsdata *livephotodata = [nskeyedarchiver archiveddatawithrootobject:livephoto];                 if ([[nsfilemanager defaultmanager] createfileatpath:url.path contents:livephotodata attributes:nil])                 {                     nslog(@"downloaded live photo:%@", url.path);                     completion();                 }             }         }];     }     else if (asset.mediatype == phassetmediatypeimage)     {         phimagerequestoptions *options = [phimagerequestoptions new];         options.networkaccessallowed = yes;         [[phimagemanager defaultmanager] requestimagedataforasset:asset options:options resulthandler:^(nsdata * _nullable imagedata, nsstring * _nullable datauti, uiimageorientation orientation, nsdictionary * _nullable info) {             if ([info objectforkey:phimageerrorkey] == nil                 && [[nsfilemanager defaultmanager] createfileatpath:url.path contents:imagedata attributes:nil])             {                 nslog(@"downloaded photo:%@", url.path);                 completion();             }         }];     }     else if (asset.mediatype == phassetmediatypevideo)     {         phvideorequestoptions *options = [phvideorequestoptions new];         options.networkaccessallowed = yes;         [[phimagemanager defaultmanager] requestexportsessionforvideo:asset options:options exportpreset:avassetexportpresethighestquality resulthandler:^(avassetexportsession * _nullable exportsession, nsdictionary * _nullable info) {             if ([info objectforkey:phimageerrorkey] == nil)             {                 exportsession.outputurl = url;                  nsarray<phassetresource *> *resources = [phassetresource assetresourcesforasset:asset];                 (phassetresource *resource in resources)                 {                     exportsession.outputfiletype = resource.uniformtypeidentifier;                     if (exportsession.outputfiletype != nil)                         break;                 }                  [exportsession exportasynchronouslywithcompletionhandler:^{                     if (exportsession.status == avassetexportsessionstatuscompleted)                     {                         nslog(@"downloaded video:%@", url.path);                         completion();                     }                 }];             }         }];     } }