Some commands may want to provide information on whether the command was successful or not. This is different
from a failure, which usually would result in an exception being thrown. An example is a putIfAbsent() not doing
anything because the key in question was present. This would result in a isSuccessful() call returning false.
true if the command completed successfully, false otherwise.
Certain commands only work based on a certain condition or state of the cache. For example, ConcurrentMap.putIfAbsent(Object, Object) only does anything if a condition is met, i.e., the entry in
question is not already present. This method tests whether the command in question is conditional or not.
true if the command is conditional, false otherwise