public void setMasterRegion(String masterRegion) {
        this.masterRegion = masterRegion;
    }
<p>
For Lambda@Edge functions, the Amazon Web Services Region of the master function. For example,
<code>us-east-1</code> filters the list of functions to include only Lambda@Edge functions replicated from a
master function in US East (N. Virginia). If specified, you must set <code>FunctionVersion</code> to
<code>ALL</code>.
</p>

@param masterRegion
       For Lambda@Edge functions, the Amazon Web Services Region of the master function. For example,
       <code>us-east-1</code> filters the list of functions to include only Lambda@Edge functions replicated from
       a master function in US East (N. Virginia). If specified, you must set <code>FunctionVersion</code> to
       <code>ALL</code>.
aws-java-sdk-lambda/src/main/java/com/amazonaws/services/lambda/model/ListFunctionsRequest.java