/// <summary>
        /// Uploads a provided file to the target parent folder.
        /// If the file already exists, an error will be thrown.
        /// A proper timeout should be provided for large uploads.
        /// </summary>
        /// <param name="fileRequest">BoxFileRequest object.</param>
        /// <param name="stream">Stream of uploading file.</param>
        /// <param name="fields">Fields which shall be returned in result.</param>
        /// <param name="timeout">Timeout for response.</param>
        /// <param name="contentMD5">The SHA1 hash of the file.</param>
        /// <param name="setStreamPositionToZero">Set position for input stream to 0.</param>
        /// <param name="uploadUri">Uri to use for upload. Default upload endpoint URI is used if not specified.</param>
        /// <returns>A full file object is returned inside of a collection if the ID is valid and if the update is successful.</returns>
        public async Task <BoxFile> UploadAsync(BoxFileRequest fileRequest, Stream stream, List <string> fields = null,
                                                TimeSpan?timeout             = null, byte[] contentMD5 = null,
                                                bool setStreamPositionToZero = true,
                                                Uri uploadUri = null)
        {
            stream.ThrowIfNull("stream");
            fileRequest.ThrowIfNull("fileRequest")
            .Name.ThrowIfNullOrWhiteSpace("filedRequest.Name");
            fileRequest.Parent.ThrowIfNull("fileRequest.Parent")
            .Id.ThrowIfNullOrWhiteSpace("fileRequest.Parent.Id");

            if (setStreamPositionToZero)
            {
                stream.Position = 0;
            }

            uploadUri = uploadUri == null ? _config.FilesUploadEndpointUri : uploadUri;

            BoxMultiPartRequest request = new BoxMultiPartRequest(uploadUri)
            {
                Timeout = timeout
            }
            .Param(ParamFields, fields)
            .FormPart(new BoxStringFormPart()
            {
                Name  = "attributes",
                Value = _converter.Serialize(fileRequest)
            })
            .FormPart(new BoxFileFormPart()
            {
                Name     = "file",
                Value    = stream,
                FileName = fileRequest.Name
            });

            if (contentMD5 != null)
            {
                request.Header(Constants.RequestParameters.ContentMD5, HexStringFromBytes(contentMD5));
            }

            IBoxResponse <BoxCollection <BoxFile> > response = await ToResponseAsync <BoxCollection <BoxFile> >(request).ConfigureAwait(false);

            // We can only upload one file at a time, so return the first entry
            return(response.ResponseObject.Entries.FirstOrDefault());
        }
        /// <summary>
        /// This method is used to upload a new version of an existing file in a user’s account. Similar to regular file uploads,
        /// these are performed as multipart form uploads. An optional If-Match header can be included to ensure that client only
        /// overwrites the file if it knows about the latest version. The filename on Box will remain the same as the previous version.
        /// To update the file’s name, you can specify a new name for the file using the fileName parameter.
        /// A proper timeout should be provided for large uploads.
        /// </summary>
        /// <param name="fileName">Name of the file.</param>
        /// <param name="fileId">Id of the file to upload a new version to.</param>
        /// <param name="stream">Stream of the uploading file.</param>
        /// <param name="etag">This ‘etag’ field of the file, which will be set in the If-Match header.</param>
        /// <param name="fields">Fields which shall be returned in result.</param>
        /// <param name="timeout">Optional timeout for response.</param>
        /// <param name="contentMD5">The SHA1 hash of the file.</param>
        /// <param name="setStreamPositionToZero">Set position for input stream to 0.</param>
        /// <param name="uploadUri">Optional url for uploading file.</param>
        /// <returns>A full file object is returned.</returns>
        public async Task <BoxFile> UploadNewVersionAsync(string fileName, string fileId, Stream stream,
                                                          string etag                  = null, List <string> fields = null,
                                                          TimeSpan?timeout             = null, byte[] contentMD5    = null,
                                                          bool setStreamPositionToZero = true,
                                                          Uri uploadUri                = null)
        {
            fileName.ThrowIfNullOrWhiteSpace("fileName");
            fileId.ThrowIfNullOrWhiteSpace("fileId");
            stream.ThrowIfNull("stream");

            if (setStreamPositionToZero)
            {
                stream.Position = 0;
            }

            uploadUri = uploadUri == null ? new Uri(string.Format(Constants.FilesNewVersionEndpointString, fileId)) : uploadUri;

            BoxMultiPartRequest request = new BoxMultiPartRequest(uploadUri)
            {
                Timeout = timeout
            }
            .Header(Constants.RequestParameters.IfMatch, etag)
            .Param(ParamFields, fields)
            .FormPart(new BoxFileFormPart()
            {
                Name     = "filename",
                Value    = stream,
                FileName = fileName
            });

            if (contentMD5 != null)
            {
                request.Header(Constants.RequestParameters.ContentMD5, HexStringFromBytes(contentMD5));
            }

            IBoxResponse <BoxCollection <BoxFile> > response = await ToResponseAsync <BoxCollection <BoxFile> >(request).ConfigureAwait(false);

            // We can only upload one file at a time, so return the first entry
            return(response.ResponseObject.Entries.FirstOrDefault());
        }
        /// <summary>
        /// This method is used to upload a new version of an existing file in a user’s account. Similar to regular file uploads, 
        /// these are performed as multipart form uploads. An optional If-Match header can be included to ensure that client only 
        /// overwrites the file if it knows about the latest version. The filename on Box will remain the same as the previous version.
        /// To update the file’s name, you can specify a new name for the file using the fileName parameter.
        /// A proper timeout should be provided for large uploads.
        /// </summary>
        /// <param name="fileName">Name of the file.</param>
        /// <param name="fileId">Id of the file to upload a new version to.</param>
        /// <param name="stream">Stream of the uploading file.</param>
        /// <param name="etag">This ‘etag’ field of the file, which will be set in the If-Match header.</param>
        /// <param name="fields">Fields which shall be returned in result.</param>
        /// <param name="timeout">Optional timeout for response.</param>
        /// <param name="contentMD5">The SHA1 hash of the file.</param>
        /// <param name="setStreamPositionToZero">Set position for input stream to 0.</param>
        /// <param name="uploadUri">Optional url for uploading file.</param>
        /// <returns>A full file object is returned.</returns>
        public async Task<BoxFile> UploadNewVersionAsync(string fileName, string fileId, Stream stream,
                                                         string etag = null, List<string> fields = null,
                                                         TimeSpan? timeout = null, byte[] contentMD5 = null,
                                                         bool setStreamPositionToZero = true,
                                                         Uri uploadUri = null)
        {
            fileName.ThrowIfNullOrWhiteSpace("fileName");
            fileId.ThrowIfNullOrWhiteSpace("fileId");
            stream.ThrowIfNull("stream");

            if (setStreamPositionToZero)
                stream.Position = 0;

            uploadUri = uploadUri == null ? new Uri(string.Format(Constants.FilesNewVersionEndpointString, fileId)) : uploadUri;

            BoxMultiPartRequest request = new BoxMultiPartRequest(uploadUri) { Timeout = timeout }
                .Header(Constants.RequestParameters.IfMatch, etag)
                .Param(ParamFields, fields)
                .FormPart(new BoxFileFormPart()
                {
                    Name = "filename",
                    Value = stream,
                    FileName = fileName
                });

            if (contentMD5 != null)
                request.Header(Constants.RequestParameters.ContentMD5, HexStringFromBytes(contentMD5));

            IBoxResponse<BoxCollection<BoxFile>> response = await ToResponseAsync<BoxCollection<BoxFile>>(request).ConfigureAwait(false);

            // We can only upload one file at a time, so return the first entry
            return response.ResponseObject.Entries.FirstOrDefault();
        }
        /// <summary>
        /// Uploads a provided file to the target parent folder.
        /// If the file already exists, an error will be thrown.
        /// A proper timeout should be provided for large uploads.
        /// </summary>
        /// <param name="fileRequest">BoxFileRequest object.</param>
        /// <param name="stream">Stream of uploading file.</param>
        /// <param name="fields">Fields which shall be returned in result.</param>
        /// <param name="timeout">Timeout for response.</param>
        /// <param name="contentMD5">The SHA1 hash of the file.</param>
        /// <param name="setStreamPositionToZero">Set position for input stream to 0.</param>
        /// <param name="uploadUri">Uri to use for upload. Default upload endpoint URI is used if not specified.</param>
        /// <returns>A full file object is returned inside of a collection if the ID is valid and if the update is successful.</returns>
        public async Task<BoxFile> UploadAsync(BoxFileRequest fileRequest, Stream stream, List<string> fields = null,
                                                TimeSpan? timeout = null, byte[] contentMD5 = null,
                                                bool setStreamPositionToZero = true,
                                                Uri uploadUri = null)
        {
            stream.ThrowIfNull("stream");
            fileRequest.ThrowIfNull("fileRequest")
                .Name.ThrowIfNullOrWhiteSpace("filedRequest.Name");
            fileRequest.Parent.ThrowIfNull("fileRequest.Parent")
                .Id.ThrowIfNullOrWhiteSpace("fileRequest.Parent.Id");

            if (setStreamPositionToZero)
                stream.Position = 0;

            uploadUri = uploadUri == null ? _config.FilesUploadEndpointUri : uploadUri;

            BoxMultiPartRequest request = new BoxMultiPartRequest(uploadUri) { Timeout = timeout }
                .Param(ParamFields, fields)
                .FormPart(new BoxStringFormPart()
                {
                    Name = "attributes",
                    Value = _converter.Serialize(fileRequest)
                })
                .FormPart(new BoxFileFormPart()
                {
                    Name = "file",
                    Value = stream,
                    FileName = fileRequest.Name
                });

            if (contentMD5 != null)
                request.Header(Constants.RequestParameters.ContentMD5, HexStringFromBytes(contentMD5));

            IBoxResponse<BoxCollection<BoxFile>> response = await ToResponseAsync<BoxCollection<BoxFile>>(request).ConfigureAwait(false);

            // We can only upload one file at a time, so return the first entry
            return response.ResponseObject.Entries.FirstOrDefault();
        }