FileSize Property MSBuild Extension Pack Help 4.0.12.0
Sets the size of the file in bytes for TaskAction="Create". This can be overridden by using a metadata tag called size on the Files items.

Namespace: MSBuild.ExtensionPack.FileSystem
Assembly: MSBuild.ExtensionPack (in MSBuild.ExtensionPack.dll) Version: 4.0.0.0
See Also

Reference