Revert "Increase the delay in the case where there are no metrics to send."

This reverts commit 950ffb26445ac973adbbc97f1ae8b4f3fe7a8701.
Revert "Reduce the number of lines per read."

This reverts commit 0f510547470f321f9c421adbd85114a735621ea4.
Revert "Merge in changes from pcn to reduce the cost of sending datapoints."

This reverts commit 79e666944994f19ab68ff650ef765cfa77458148.