def wf_distribution?(dist)
      wf_metric_name?(dist[:path])
      wf_distribution_values?(dist[:value])
      wf_epoch?(dist[:ts]) if dist[:ts]
      wf_source_id?(dist[:source]) if dist[:source]
      wf_point_tags?(dist[:tags]) if dist[:tags]
      true
    end
def wf_distribution?(dist)
      wf_metric_name?(dist[:path])
      wf_distribution_values?(dist[:value])
      wf_epoch?(dist[:ts]) if dist[:ts]
      wf_source_id?(dist[:source]) if dist[:source]
      wf_point_tags?(dist[:tags]) if dist[:tags]
      true
    end
Validate a distribution description
 @param dist [Hash] description of distribution
 @return true if valid
 @raise whichever exception is thrown first when validating
   each component of the distribution.