What is the difference between a partially blocking transformation versus a fully blocking transformation in SQL Server Integration Services?

Asynchronous transformations, as discussed in last question, can be further divided in two categories depending on their blocking behavior: 

Partially Blocking Transformations do not block the output until a full read of the inputs occur. However, they require new buffers/memory to be allocated to store the newly created result-set because the output from these kind of transformations differs from the input set. 

For example, Merge Join transformation joins two sorted inputs and produces a merged output. In this case if you notice, the data flow pipeline engine creates two input sets of memory, but the merged output from the transformation requires another set of output buffers as structure of the output rows which are different from the input rows. It means the memory requirement for this type of transformations is higher than synchronous transformations where the transformation is completed in place. 

Full Blocking Transformations, apart from requiring an additional set of output buffers, also blocks the output completely unless the whole input set is read. 

For example, the Sort Transformation requires all input rows to be available before it can start sorting and pass down the rows to the output path. These kind of transformations are most expensive and should be used only as needed. For example, if you can get sorted data from the source system, use that logic instead of using a Sort transformation to sort the data in transit/memory