AWS SDK for .NET Documentation
InputStream Property
AmazonAmazon.S3.UtilS3PostUploadRequestInputStream Did this page help you?   Yes   No    Tell us about it...
Stream to read the upload data for
Declaration Syntax
C#
public Stream InputStream { get; set; }
Remarks
If you use InputStream, then you also need to set ContentLength

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)