Returns the closest long to a. If equally close to two values, return the one closer to ##Inf. If a is ##NaN => 0 If a is ##-Inf or < Long/MIN_VALUE => Long/MIN_VALUE If a is ##Inf or > Long/MAX_VALUE => Long/MAX_VALUE See: https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#round-double-