Low level interface function to the IBM ILOG CPLEX function
  CPXflushchannel.  Consult the IBM ILOG CPLEX documentation for more
  detailed information.
flushChannelCPLEX(env, newch)An object of class "'>cplexPtr" as returned by
    openEnvCPLEX. This is basically a pointer to an
    IBM ILOG CPLEX environment.
Pointer to a channel object as returned by addChannelCPLEX.
NULL
Interface to the C function flushChannel which calls the CPLEX
  function CPXflushchannel.
The IBM ILOG CPLEX home page at https://www.ibm.com/support/knowledgecenter/SSSA5P.
disconnectChannelCPLEX, flushStdChannelsCPLEX,
  getChannelsCPLEX