presto-main/src/main/java/io/prestosql/execution/buffer/OutputBuffers.java/OutputBuffers/OutputBuffers
class OutputBuffers:    @JsonCreator
    public OutputBuffers(
            @JsonProperty("type") BufferType type,
            @JsonProperty("version") long version,
            @JsonProperty("noMoreBufferIds") boolean noMoreBufferIds,
            @JsonProperty("buffers") Map<OutputBufferId, Integer> buffers)
    {
        this.type = type;
        this.version = version;
        this.buffers = ImmutableMap.copyOf(requireNonNull(buffers, "buffers is null"));
        this.noMoreBufferIds = noMoreBufferIds;
    }