public static <A> MemoryComputeKey<A> of(final String key, final BinaryOperator<A> reducer, final boolean isBroadcast, final boolean isTransient) {
        return new MemoryComputeKey<>(key, reducer, isBroadcast, isTransient);
    }
A {@code MemoryComputeKey} specifies what keys will be used by a {@link Memory} during a {@link GraphComputer} computation.
A MemoryComputeKey maintains a {@link BinaryOperator} which specifies how to reduce parallel values into a single value.
A MemoryComputeKey can be broadcasted and as such, the workers will receive mutations to the {@link Memory} value.
A MemoryComputeKey can be transient and thus, will not be accessible once the {@link GraphComputer} computation is complete.

@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/MemoryComputeKey.java