public long connectionAcquisitionDurationNanos() {
        return connectionAcquisitionDurationNanos;
    }
Returns the duration which was taken to get a connection, in nanoseconds. This value is greater than or
equal to the sum of {@link #dnsResolutionDurationNanos()}, {@link #socketConnectDurationNanos()} and
{@link #pendingAcquisitionDurationNanos()}.
core/src/main/java/com/linecorp/armeria/common/logging/ClientConnectionTimings.java