+ executing command.
+
+ The server aborts the command on interrupt and EOF. Any argument
+ prompts it may send before the next command prompt do not consume
+ input. On EOF, the server then enters the shutdown phase (but see
+ C_EXECUTE for an exception).
+
+ If an update runs while the server waits for the line of input to
+ arrive, the current command is aborted. Whether the server consumes
+ a line of input for this argument prompt is unpredictable. Any
+ argument prompts it may send before the next command prompt do not
+ consume input.