Add assertion for Copied Object
Add assertion for Copied Object

Change-Id: I054522f977e778378ac5331154ad22e08d3c2d59

KoreaCloudObjectStorage/swift3,swiftstack/swift3-stackforge,tumf/swift3,KoreaCloudObjectStorage/swift3,swiftstack/swift3-stackforge,stackforge/swift3,stackforge/swift3,tumf/swift3