public HdfsSystemDescriptor withConsumerBufferCapacity(long bufferCapacity) {
    this.consumerBufferCapacity = Optional.of(bufferCapacity);
    return this;
  }
The capacity of the hdfs consumer buffer - the blocking queue used for storing messages.
@param bufferCapacity the buffer capacity for HDFS consumer.
@return this system descriptor
samza-hdfs/src/main/java/org/apache/samza/system/hdfs/descriptors/HdfsSystemDescriptor.java