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 Server indicated by the user as an argument to the
ServerLauncher. This PID will be used by the Server launcher to determine the Server's
status, or invoke shutdown on the Server.

@param pid a user specified Integer value indicating the process ID of the running Server.
@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/ServerLauncher.java