public final void setShutDownThreadPools(Boolean shutDownThreadPools) {
        this.shutDownThreadPools = shutDownThreadPools;
    }
By default, when the transfer manager is shut down, the underlying {@link ExecutorService} is
also shut down. For cases where the same thread pool is reused across different workloads you
can set this option to false to disable that behavior.

@param shutDownThreadPools True to shut down thread pools on transfer manager shutdown, false
                           otherwise.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/transfer/TransferManagerBuilder.java