td_add                  Add a value to the t-Digest with the specified
                        count
td_create               Allocate a new histogram
td_merge                Merge one t-Digest into another
td_quantile_of          Return the quantile of the value
td_total_count          Total items contained in the t-Digest
td_value_at             Return the value at the specified quantile
tquantile               Calculate sample quantiles from a t-Digest
