public AttachmentsSource withKey(AttachmentsSourceKey key) {
        this.key = key.toString();
        return this;
    }
<p>
The key of a key-value pair that identifies the location of an attachment to a document.
</p>

@param key
       The key of a key-value pair that identifies the location of an attachment to a document.
@return Returns a reference to this object so that method calls can be chained together.
@see AttachmentsSourceKey
aws-java-sdk-ssm/src/main/java/com/amazonaws/services/simplesystemsmanagement/model/AttachmentsSource.java