public Builder setPid(final Integer pid) {
      if (pid != null && pid < 0) {
        throw new IllegalArgumentException(
            "A process ID (PID) must be a non-negative integer value.");
      }
      this.pid = pid;
      return this;
    }
Sets the process ID (PID) of the running Locator indicated by the user as an argument to the
LocatorLauncher. This PID will be used by the Locator launcher to determine the Locator's
status, or invoke shutdown on the Locator.

@param pid a user specified Integer value indicating the process ID of the running Locator.
@return this Builder instance.
@throws IllegalArgumentException if the process ID (PID) is not valid (greater than zero if
        not null).
@see #getPid()
geode-core/src/main/java/org/apache/geode/distributed/LocatorLauncher.java