pub fn parse_b3(
b3_single: Option<&str>,
trace_id: Option<&str>,
span_id: Option<&str>,
sampled: Option<&str>,
) -> Option<(String, String, bool)>Expand description
Parses B3 propagation from either the single b3 header
(trace-span-sampled-parent) or the multi-header form, given a lookup of
the relevant request headers, into (trace_id, parent_span_id, sampled).