Open a path-based source once, process-wide, synchronously. Returns the shared instance (opening it on the first call), or undefined if the path needs async opening (a .br/.gz bundle, use getSharedSigSource); throws on any other open failure.
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.gz
Open a path-based source once, process-wide, synchronously. Returns the shared instance (opening it on the first call), or
undefinedif the path needs async opening (a.br/.gzbundle, use getSharedSigSource); throws on any other open failure.