BloombergLP::bdld::operator<<

Write the specified rhs value to the specified output stream in the format shown below: ` [ abc = aa, pqr = bb]‐ abc and pqr are key strings, while aa and bb are the result of invoking operator '<<' on the individual value elements in the map ` and return a reference to the modifiable stream. The function will have no effect if the stream is not valid.