/** B3 single-header key */
export declare const B3_CONTEXT_HEADER = "b3";
export declare const X_B3_TRACE_ID = "x-b3-traceid";
export declare const X_B3_SPAN_ID = "x-b3-spanid";
export declare const X_B3_SAMPLED = "x-b3-sampled";
export declare const X_B3_PARENT_SPAN_ID = "x-b3-parentspanid";
export declare const X_B3_FLAGS = "x-b3-flags";
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