Construct clients on demand (#6920)
Construct clients on demand (#6920)

They're cheap to construct

This will help me add round-robining between multiple servers.
twitter/pants,tdyas/pants,twitter/pants,pantsbuild/pants,jsirois/pants,pantsbuild/pants,wisechengyi/pants,benjyw/pants,benjyw/pants,jsirois/pants,tdyas/pants,twitter/pants,wisechengyi/pants,jsirois/pants,twitter/pants,benjyw/pants,tdyas/pants,wisechengyi/pants,pantsbuild/pants,pantsbuild/pants,tdyas/pants,wisechengyi/pants,benjyw/pants,pantsbuild/pants,benjyw/pants,twitter/pants,tdyas/pants,wisechengyi/pants,wisechengyi/pants,wisechengyi/pants,wisechengyi/pants,tdyas/pants,twitter/pants,benjyw/pants,tdyas/pants,wisechengyi/pants,tdyas/pants,twitter/pants,pantsbuild/pants,benjyw/pants,tdyas/pants,twitter/pants,pantsbuild/pants,twitter/pants