Did not expect this wait event "SQL*Net message from client"

I am wondering why I am getting this wait event during a standard SQL*Plus execution of a sql script.

This is the SQL script :

variable B2 number;

exec :B2 := 4;

variable B1 number;

exec :B1 := 20160331;

set timing on;

set autotrace traceonly;

ALTER SESSION SET EVENTS '10046 trace name context forever, level 8';

spool go.lst;

select * from

  L2_PROFIT_LOSS PL

INNER JOIN L2_CTPY_FI_MAPPING IPFI

            ON PL.IDE_INTERNAL_PARTY_REF = IPFI.IDE_COUNTERPARTY_REF

            AND PL.VALID_ON = IPFI.VALID_ON

            AND PL.LOT_TYPE_FK = IPFI.LOT_TYPE_FK

     and pl.lot_type_fk=4

     and pl.valid_on=20160331